Papers relevant to the study of Dunlins:
references, abstracts and comments. Where there is no abstract, an abstract has been written, where abstracts are too long they have been abridged. Abstracts in languages other than English have been translated into English. Some 200 papers will be entered to start with. The comment is personal, it points out errors and possible follow-ups, it is begun: CP:
(There is an overall problem from the early or mid-nineties: editors are unable to evaluate the worth or substance of empirics, therefore a couple of serious errors are in circulation right now; nobody notices them and nobody cares. Publishing as an invitation to public discussion doesn't function any longer, and I think this is part of a paradigm crisis to come - or already in progress. The only instance I could think of to address the problem is Wader Study Group - but it should not be done in writing - I think some sort of panel discussions over topics like "Do waders migrate and moult at the same time?", "Do juvenile Dunlin migrate unaccompanied by adults?" and "Is the progress of young Dunlin "trial and error"?" are necessary. This in order to keep the people involved from evading and ducking: both the authors responsible and the difficult questions must be confronted).
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Kania, W. (1990): The primary moult of breeding Dunlins Calidris alpina in the central Taimyr in 1989. Wader Study Group Bull. 60: 17 - 19.
Kaukola, A. & I. Lilja. (1972): Migration of Calidris and Limicola species at Yyteri in 1961 - 69. Porin Lint. Yhd. Vuosikirja 1972: 17 - 23 (In Finnish with English summary).
Kelly, J.P. (2001): Hydrographic correlates of winter Dunlin abundance and distribution in a temperate estuary. Waterbirds 24: 309 - 322. Link to JSTOR
From 1989 to 1999, I examined intra-seasonal and annual changes in the abundance and local distribution of two groups of wintering Dunlin (Calidris alpina) occupying different positions along hydrographic gradients in the Tomales Bay estuary, California. Reciprocal translocation of color-banded Dunlin indicated a discrete separation of wintering Dunlin between the north and south of Tomales Bay. Local abundance in both groups was significantly associated with cumulative seasonal rainfall within and among years. Increased variation in annual and intra-seasonal abundance was related to reduced tidal circulation, greater freshwater stream flow, and increased salinity variation. On average, winter Dunlin use peaked later but declined earlier in the southern part of the bay (near the head of the bay) than in the northern part of the bay (near the mouth of the bay). Shifts in distribution associated with changes in hydrographic conditions and weather revealed consistent intra-seasonal changes in habitat preference on temporal scales other than tidal cycles. In the northern part of the bay, changes in habitat preference by Dunlin corresponded to thresholds of 20-25 cm cumulative rainfall and 0.5-1.0 m3 sec-1 stream flow, whereas in the south bay changes were relatively continuous. Rainfall, wind velocity and direction, and temperature also influenced habitat preferences. Flocking behavior dominated over habitat choice at low levels of Dunlin abundance, resulting in contrasting patterns of habitat use relative to overall trends. These patterns suggested the loss of habitat quality as the criterion for patch use. In general, this study indicates that winter shorebird use of temperate estuaries can be predicted by differences in weather and hydrographic regimes, including rates and variances of freshwater inflow, estuarine circulation, and water residence times unique to each system.
Kelly, J.P. et al. (2002): Effects of weather on daily body mass regulation in wintering dunlin. J. Exp. Biol. 205: 109 - 120.
Kelly, J. P., Warnock, N., Page, G. W. & W. W. Weathers (2002): Effects of weather on daily body mass regulation in wintering dunlin. J. Exp. Biol. 205: 109 - 120. Internet version of this paper.
We investigated the influence of changes in weather associated with winter storms on mass balance, activity and food consumption in captive dunlin (Calidris alpina) held in outdoor aviaries, and compared the aviary results with weather-related body mass differences in free-living dunlin collected at Bolinas Lagoon, California. Captive birds fed ad libitum increased their body mass at higher wind speeds and lower temperatures, suggesting regulation of energy stores, whereas free-living birds exhibited patterns suggesting thermoregulatory limits on body mass regulation. Daily energy expenditure in aviary dunlin was 2.85 kJ g d-1, or 2.8x basal metabolic rate (BMR), with thermostatic costs averaging 59 % of daily expenditure. Slight but significant increases in body mass and energy expenditure in captive birds on rainy days, adjusted for possible external water mass, suggested rainfall as a proximate cue in regulating daily body mass. Body mass changes under artificial rainfall indicated similar results, and field masses suggested that free-living birds have greater body mass on days with measurable rainfall. Increased activity costs under artificial rainfall were associated with an increase in maintenance activities, relative to controls. Whether activity costs increased on days with natural rates of rainfall was unclear. Our results are consistent with current hypotheses regarding the role of body mass regulation in providing insurance against increased starvation risk during deteriorating thermal or foraging conditions, or in reducing the costs of extra mass as conditions improve.
Kelly, J. P. & W. W. Weathers (2002): Effects of feeding time constraints on body mass regulation and energy expenditure in wintering dunlin (Calidris alpina). Behav. Ecol. 13: 766 - 775.
Kim, H.-B., Yoo, J.-C. & P.-O. Won (1994): Seasonal fluctuations, biometrics, fat and non-fat masses of Dunlins Calidris alpina sakhalina migrating to Sammok Island on the west coast of Korea. Kor. J. Ornithol. 1: 15-24.
King, J. R. (1981): Energetics of avian moult. Proc. 17th Int. Orn. Congr. 312 - 317.
Klaassen, M. & B. J. Ens (1990): Is salt stress a problem for waders wintering on the Banc d'Arguin, Mauritania? Ardea 78: 67 - 74.
Koffijberg, K., Blew, J., Eskildsen, K., Günther, K., Koks, B., Laursen, K., Rasmussen, L. M., Potel, P. & P. Südbeck (2003): High tide roosts in the Wadden Sea: A review of bird distribution, protection regimes and potential sources of anthropogenic disturbance. Wadden Sea Ecosystem No. 16. Common Wadden Sea Secretariat. pdf download on the web
Kolthoff, G. (1896): Zur Herbstwanderung der nordischen Sumpfvögel über die Insel Öland. Festskrift för Liljeborg, 121 - 136. Uppsala.
Kraaijeveld, K. & E. N. Nieboer. (2000): Late Quaternary Paleography and Evolution of Arctic breeding waders. Ardea 88: 193 - 205. Internet version of this paper.
This review links published data on mitochondrial DNA phylogeography of
three wader species breeding in the Arctic to the availability of suitable breeding habitat during the past 250 000 years. We argue that the breeding ranges of arctic waders were most restricted in size during warm phases in the earth's climate (interglacials), resulting in population bottlenecks in species breeding in the high arctic zone, such as Red Knot Calidris canutus and Ruddy Turnstone Arenaria interpres, and population contraction and the initiation of genetic divergence in low arctic species, such as Dunlin
Calidris alpina. When the climate cooled, all species could spread over larger areas. However, large ice-sheets fragmented tundra habitat, which resulted in more differentiation. Subspecies of Dunlin that became isolated during or before the last glacial period are genetically distinct, while those that originated after the glacial cannot be distinguished using mitochondrial DNA. The sensitivity of waders breeding in the high Arctic to increases
in global temperature raises concerns over the effect of possible global warming due to anthropogenic factors on these species.
Krol, E. (1985): Numbers, reproduction and breeding behaviour of Dunlin Calidris alpina schinzii at the Reda mouth, Poland. Acta orn. 21: 69 - 94.
Kube, J., H.-U. Rösner, H. Behmann, U. Brenning & J. Gromadzka (1994): Der Zug des Alpenstrandläufers (Calidris alpina) an der südlichen Ostseeküste und im Schleswig-Holsteinischen Wattenmeer im Sommer und Herbst 1991. Corax, Sonderheft 2: 73 - 82.
In the late summer and autumn of 1991 migrating Dunlin (Calidris alpina) were counted along the south Baltic coast and in the Waddensea parts of Schleswig-Holstein. In all Baltic
areas there were three waves of migrating adults and one wave of migrating juveniles. A sharp rise in Waddensea numbers coincides with the first Baltic wave of adults, a second rise in September with the wave of juveniles. Based on estimates of the maximum amount of resting adults and juveniles along the Baltic shores, and catching results from the mouth of Vistula (Poland) and the isle of Langenwerder, a minimum value for the overall passage of migrant Dunlin in this area can be calculated. Relatively few adults visit German and Polish shores: only 1 - 2 % of the total population, while more than 10 % of the juvenile population stays for some time in the same area.
Kus, B. E., Ashman, P., Page, G. W. et al. (1984): Age related mortality in a wintering population of dunlin. Auk 101: 69 - 73.
Laczik, D. & A. Pellinger (2006): Migration dynamics and moult at an inland stopover site: autumn migration of dunlin (Calidris alpina) at Lake Fertö, North-west Hungary. Limnology and Waterbirds Conference, 2006. Abstract of oral presentation.
In this study the main characteristics of migration were investigated in North-west Hungary at Lake Ferto.
The results of ringing between 1992-2003 revealed that primarily juvenile Dunlins stopped at the area during migration. The ratio of adults was about 1% of the captured birds. Weekly censuses between 1998-2003 showed that there were two - occasionally three - migratory waves each autumn cumulating in mid September and early October. Feeding activity of Dunlins increased at night, though birds foraging in the daytime could also be observed when migration was at its peak. Investigating the moult of adult birds, four stages were found, suggesting mixed origin of the flocks.
Average stopover length was longer and relative change of body mass was significantly higher at the beginning of the migration than at the end of it. Pattern of body mass change was different at birds having arrived earlier than those appearing later, the latter group being characterized by a flatter curve.
According to the timing of migration and biometrical measurements, the nominate subspecies Calidris alpina alpina appears regularly at this stopover site. Direct and indirect recoveries provide an evidence of loop migration.
Lane, B. & A. Jessop (1985): Tracking of migrating waders in north-western Australia using meteorological radar. Stilt 6: 17 - 28.
Lappo, E. G. & P. Tomkovich (1998): Breeding distribution of Dunlin Calidris alpina in Russia. International Wader Studies 10: 152 - 169. Web version of this paper
Breeding records and breeding densities available from the literature, museum collections and unpublished data are summarised for six subspecies of Dunlin Calidris alpina in Russia. Differences in distribution and habitats found in supspecies and populations are used to outline their breeding ranges. Each subspecies or population has core areas where densities are high and habitats most diverse, but it was not possible to discover such core areas for all subspecies. Maximum densities are not the same in different subspecies, thus centralis never reaches densities that are as high as found in alpina, sakhalina and kistchinski. Coastal areas are often the most densely populated in European tundra and in the Far East. Dunlin avoid dense stands of dwarf birch possibly because large hydrophilous Enchytraeidae worms, their main food, are scarce there. This is probably the reason for Dunlin having a patchy distribution in southern tundra; only isolated breeding localities on bogs are known in areas where large dwarf-birch tundra belt is present.
Lavers, C. P. & R. H. Haines-Young (1996): The pattern of Dunlin Calidris alpina distribution and abundance in relation to habitat variation in the Flow Country of northern Scotland. Bird Study 43: 231 - 239. Internet version of this paper
The object of the research reported here was to produce a map of habitat quality for the Dunlin across the Flow Country of northern Scotland for use in conservation and land-use planning. The region is too large (ca. 1800 km2) to survey on foot without significant expenditure of time and resources. Habitat quality was therefore predicted by relating Dunlin density recorded on a set of sample sites in the region to vegetation and landform characteristics. Density was then extrapolated across the whole region based on the recurrence of similar habitat conditions. The abundance of Dunlin in the Flow Country is shown to be related to several different classes of environmental variation. Dunlin are absent from several easily delimited types of habitat (e.g. lochs and woodland). A presence/absence map of habitat quality for the species is achieved simply by mapping these habitat features. Abundance on the moorland that remains is related to vegetation characteristics and the presence of clusters of pools (pool-systems). Dunlin prefer areas of moorland with short, sparse vegetation. However, within such sites, regardless of vegetation type, Dunlin density varies systematically with respect to pool-systems, increasing exponentially as these habitat features are approached. Density variation with respect to changes in vegetation characteristics and pool-systems were modelled to produce a map of habitat quality within a 1 ha grid over the whole region.
Lavers, C. P., Haines-Young, R. H. & M. I. Avery (1996): The habitat associations of dunlin (Calidris alpina) in the Flow Country of northern Scotland and an improved model for predicting habitat quality. J. Appl. Ecol. 33: 279 - 290.
Lavers, C. & R. H. Haines-Young (1997): The use of satellite imagery to estimate Dunlin Calidris alpina abundance in Caithness and Sutherland and in the Shetland Islands. Bird Study 44: 220 - 226. Internet version of this paper.
Previous studies have shown a relationship between the number of Dunlin breeding on moorland sites in Caithness and Sutherland and the near-infrared reflectance of the sites measured from satellite imagery. We test the generality of this relationship using two images of Caithness and Sutherland recorded 12 years apart, and new imagery and survey data from the Shetland Islands. The correlation between Dunlin abundance and near-infrared reflectance is similar using both images of Caithness and Sutherland but no correlation is apparent in Shetland. This regional difference is explained by relating the spectral characteristics of sites in both study areas to ground cover data recorded from field surveys.
Lavers, C.P. & R. H. Haines-Young (1997): Displacement of dunlin Calidris alpina schinzii by forestry in the flow country and an estimate of the value of moorland adjacent to plantations. Biol. Cons. 79: 87 - 90.
Leslie, R. & C. M. Lessells (1978): The migration of Dunlin Calidris alpina through northern Scandinavia. Orn. Scand. 9: 84 - 86.
Observations made on the Varangerfjord, N.E. Norway, during 1974 indicate that there is a large Dunlin passage through the area. Ringing recoveries suggest that juveniles which pass through the area during August move down the west coast of Norway, whilst adults, moving through during July, take a more easterly route, moving overland to the Gulf of Bothnia and into the Baltic.
CP:This is a stenographic, non-transparent paper, representing the worst of the British tradition (later on in particular: Bird Study) by this time. The suggestions by the authors have been treated as statements when quoted, but none of these statements can be critically assessed. A "juvenile route" along the Norwegian west coast was established here, adults were said to be channeled by way of the Baltic - and all problems, difficulties, complications were swept under the carpet. I would very much like to see juv : ad ratios from the Norwegian west coast, I would like to see figures describing the overall catching period, and I would like to know if this catching period coincides with the migration period of Dunlin in Norway. And: is the age-determination of late Dunlin reliable in the Norwegian case?
Lesterhuis, A. J. & R. P. Clay (2003): The first record of Dunlin (Calidris alpina) in Paraguay and a summary of South American records of the species. El Hornero 18, Internet version of the report
A Dunlin (Calidris alpina) in full breeding plumage was discovered at Laguna Ganso in the Paraguayan Chaco on 29 June 2001. This bird represents the first record of the species for the country and for the interior of South America. Although primarily a species of higher northern latitudes, there are a number of previous records from coastal South America.
Lindström, Å. & T. Piersma (1993): Mass change in migrating birds: the evidence for fat and protein storage re-examined. Ibis 135: 70 - 78.
Lindström, Å., Visser, G. H. & S. Daan (1993): The energetic cost of feather synthesis is proportional to basal metabolic rate. Phys. Z. 66: 490-510.
(...)The cost of feather synthesis was estimated at 836 and 683 kJ per (g dry feathers) in the bluethroats and redpolls, respectively. (...) The Cf for a species with known BMRm may be estimated from the equation Cf = 270BMRm. Species with a relatively high BMRm for their size also have a relatively high Cf. The tight association of Cf and BMRm between species, and the low efficiency values of feather synthesis, suggests that feather production costs include more than the costs for keratin synthesis: they mainly consist of costs of maintaining tissues necessary for feather production.
Lopes, R. J, Múrias, T., Cabral, J. A., & J. C. Marques (2005): A Ten Year Study of Variation, Trends and Seasonality of a Shorebird Community in the Mondego Estuary, Portugal. Waterbirds 28: 8 - 18.
A monthly shorebird census in Mondego estuary, Portugal was made during ten years (1993-2002) and the information adds to the midwinter census carried out at international level. It is shown that higher variability in shorebird community occurred during the breeding and migrating periods, while the winter assemblage was very similar among years. The study provides precise information of the importance of the Mondego estuary, and the trends and phenology of its shorebird community. Six species are responsible for a large proportion of the total abundance throughout the year. Dunlin (Calidris alpina) is the most abundant species, followed by the Avocet (Recurvirostra avosetta). Over the study period, there was a significant increase in the total number of shorebirds that occur in some months. This was mainly due to the increase of the main species, the Dunlin. Only the Avocet showed a significant decrease in abundance. These trends were not explained by changes in overall flyway population or the Portuguese totals. Therefore, local explanations need to be considered (e.g., changes on habitat quality).
Lopes, R. J., Marques, J. C. & L. Wennerberg (2006): Migratory connectivity and temporal segregation of dunlin ( Calidris alpina) in Portugal: evidence from morphology, ringing recoveries and mtDNA. J. Orn. 147: 385 - 394. Internet version of this paper.
Migratory connectivity plays an important role in conservation of long-distance migrant birds. Here, we study migratory links of dunlin (Calidris alpina), focusing on a stopover and wintering region (Portugal) where it is known that migration routes of dunlin from a broad geographic range (three subspecies) converge, and populations occur simultaneously or separated in time. We combine three methods (ringing recoveries, morphometrics and molecular genetics) to assess breeding origins and extent of temporal segregation of dunlin assemblages. Ringing recoveries show temporal separation of dunlin from di.erent migration routes. Birds found in Portugal during August and September, migrating via Britain, reveal links to breeding areas in Iceland and Greenland. In October, a clear shift to more eastern migration routes occurs, with most Portuguese winter records from stopover sites along migration routes of populations from northern Scandinavia and Russia. Mitochondrial DNA (mtDNA) of Portuguese dunlin was compared with breeding populations. Spring and autumn migrants in Portugal corresponded to C. a. schinzii and C. a. arctica populations, while the Portuguese winter population clearly differs by including mtDNA haplotypes of C. a. alpina. For genetically sexed individuals, we found significant differences in morphology (bill and tarsus length) supporting the temporal separation of populations/subspecies revealed by recoveries and mtDNA. Our results give evidence for migratory connectivity of dunlin populations between geographic areas previously not considered connected. They confirm the existence of clear differences in breeding origin between birds in Portugal at different times of year. These results are important in the consideration of future long-term conservation plans.
Lopes, R. J., Hortas, F. & L. Wennerberg (2008): Geographical segregation in Dunlin Calidris alpina populations wintering along the East Atlantic migratory flyway - evidence from mitochondrial DNA analysis. Diversity and Distributions 14: 732 - 741.
Dunlin Calidris alpina is one of the most abundant shorebirds using coastal habitats in the East Atlantic migratory flyway, that links arctic breeding locations (Greenland to Siberia) with wintering grounds (West Europe to West Africa). Differential migration and winter segregation between populations have been indicated by morphometrics and ringing recoveries. Here, we analyse the potential of genetic markers (mitochondrial DNA – mtDNA) to validate and enhance such findings. We compared mtDNA haplotypes frequencies at different wintering sites (from north-west Europe to West Africa). All birds from West Africa had western (European) haplotypes, while the eastern (Siberian) haplotypes were only present in European winter samples, reaching higher frequencies further north in Europe. Compilation of published results from migrating birds also confirmed these differences, with the sole presence of European haplotypes in Iberia and West Africa and increasingly higher frequencies of Siberian haplotypes from south-west to north-west Europe. Comparison with published haplotype frequencies of breeding populations shows that birds from Greenland, Iceland, and North Europe were predominant in wintering grounds in West Africa, while populations wintering in West Europe originated from more eastern breeding grounds (e.g. North Russia). These results show that genetic markers can be used to enhance the integrative monitoring of wintering and breeding populations, by providing biogeographical evidence that validate the winter segregation of breeding populations.
CP: The problem with this kind of approach was evident already from the first papers by Wenink et al.; still it appears on the scene again and again, saying little more than: Guten Morgen! In my opinion it is very important that we revive the available morphological/biometrical knowledge and apply it to the real, and interesting, problems: (1) different migration routes in different autumns (and even in individuals between years), (2) diffuse redistribution in winter and spring, leading to different staging areas in different springs (and even in individuals between years). Such shifts of course have an impact on the net distribution of populations, too. The MTDNA studies are so focused on their own "thing" that they - as the decades go by - merit little more than a yawn for their perpetual variations on one-and-the-same theme. They don't represent "true conditions", instead they are a time-limited abstraction, very far from any dynamic and continuously shifting "reality".
Luís, A., Goss-Custard, J. D. & M. H. Moreira (2002): The feeding strategy of the dunlin (Calidris alpina L.) in artificial and non-artificial habitats at Ria de Aveiro, Portugal. Hydrobiologia 475-476: 335 - 343.
Luis, A. & J. Goss-Custard (2005): Spatial organization of the Dunlin Calidris alpina L. during winter - the existence of functional units. Bird Study 52: 97-103. Internet version of this paper.
Aims To examine the way in which wintering Dunlin organize and distribute themselves in a coastal lagoon. Methods Data collection was undertaken in the Mira Canal and in a salt-pan zone over five winters, mostly using counting, bird ringing and radiotracking. Results Birds restricted their activities to limited sectors of the lagoon, adopting behaviour which they maintained throughout winter. Conclusion The area of the Ria may, therefore, be divided into functional units, i.e. a group of feeding areas and high-tide roosts used by a group of birds, during a certain period of time, corresponding, for example, to winter. This type of spatial organization, already identified in ducks, has not previously been described in waders.
Maclean, S. F. & R. T. Holmes (1971): Bill lengths, wintering areas, and taxonomy of North American Dunlins, Calidris alpina. The Auk 88: 893 - 901. Internetversion of this paper.
The Dunlins that breed on arctic tundra of North America are separable into three distinct groups on the basis of bill length, with those of northern Alaska having shorter bills than those of western Alaska or north central Canada. The Dunlins of northern Alaska do not winter in North America but cross the Bering Straits to winter along the Pacific coast of Asia. The Dunlins of northeast Siberia, which also winter along the east Asian coast, have bills indistinguishable from those of northern Alaskan birds. These two populations should be included together in C. alpina sakhalina. The name C. a. pacifica should be restricted to the birds that breed in western Alaska and winter along the Pacific coast of North America. The name C. a. budsonia, first used by Todd (1953), is applied to Dunlins that breed in north central Canada and winter along the east coast of North America. The selective pressures influencing the evolution of bill length include the size and kind of prey species available for exploitation and the presence or absence of ecologically similar species that might compete for the same food items. Geographic variation in these parameters is discussed.
[CP]: This paper should be read as evidence of poor statistical treatment - or general knowledge - of two American workers by this time (1971), but it's still evident that the subspecies arcticola has a shorter bill than subspecies pacifica and hudsonia. After 1971 it seems to me as if there has been no serious treatment of the morphology of Nearctic Dunlins - genetics has attracted all interest. So, there is still a lot to be done in morphology!
Marthinsen, G., Wennerberg, L. & J. T. Lifjeld (2007): Phylogeography and subspecies taxonomy of dunlins (Calidris alpina) in western Palearctic analysed by DNA microsatellites and amplified fragment length polymorphism markers. Biol. Jour. Linn. Soc. 92: 713 – 726. Link to this paper.
In a circumpolar wader, the dunlin (Calidris alpina), there are 11 named subspecies, but only five mitochondrial DNA (mtDNA) lineages have been found. In the present study, we investigated the genetic structure of dunlins in western Palearctic (from East Greenland to Taimyr peninsula) using DNA microsatellites and amplified fragment length polymorphism (AFLP) markers that may detect more recent differentiation than mtDNA. In this region, we consider four described subspecies; alpina, schinzii, arctica and centralis, together comprising two mtDNA lineages. We analyse seven polymorphic microsatellite loci and 91 AFLP markers in 287 and 152 unrelated individuals, respectively, originating from 17 populations. Neither microsatellites nor AFLPs reveal distinct groups that correspond to currently recognized subspecies. There is a clear pattern of isolation by distance in microsatellites. Our results do not contradict the former mtDNA results that there are two phylogenetic lineages (approximately corresponding to schinzii and centralis) that have met and formed a cline (alpina). We find no difference between schinzii and arctica (East Greenland). We conclude that, given the lack of distinct groups and the gradual changes in microsatellite allele frequencies, these markers provide little genetic support for the dunlin subspecies taxonomy in the western Palearctic.
Marthinsen, G., Wennerberg, L., Pierce, E. P. & J. T. Lifjeld (2008): Phylogeographic origin and genetic diversity of dunlin Calidris alpina in Svalbard. Polar Biology, Online. Link to this paper.
We investigated the genetic structure of the presumably small (10-100 pairs) and isolated dunlin (Calidris alpina) population breeding in Svalbard, and compared it with similar data recently published from several dunlin populations in the western Palearctic and East Greenland. Using mitochondrial and nuclear DNA markers, as well as data on bill lengths, we sought to infer the phylogeographic origin of Svalbard Dunlins and assess their within-population level of genetic diversity. Only dunlins with haplotypes of the European mtDNA clade (EUR) were found in Svalbard, indicating a close resemblance to dunlin populations in East Greenland and Iceland. Microsatellite data for Svalbard dunlins, as well as their short bills, also supported a western origin. The Svalbard population did not show signs of inbreeding or reduced levels of genetic diversity compared to other investigated populations, which suggests that the population was recently founded or is currently subject to substantial gene flow.
Martin-Löf, P. (1958): Storleksskillnader hos genomsträckande kärrsnäppor (Calidris alpina) vid Ottenby. Vår Fågelvärld 17: 287 - 301. This paper has a summary, part of it is quoted here.
Measurements of bill, wing, and total length of 1.112 dunlins (99 % juvenile birds of the year) trapped for ringing at Ottenby bird station, on the island of Öland, during three weeks in August and September 1957 show that considerable differences in size exist between birds from the earlier and birds from the later part of this period.
This was demonstrated by splitting the material into three groups, each representing a period of one week: 26 Aug. - 1 Sept. (443 inds.), 2 - 8 Sept. (322 inds.), and 15 - 21 Sept. (347 inds.); no measurements were taken between Sept. 8 and 15. (...) While bill-size proved very uniform between the three groups, there was a small but quite significant decrease in winglength between the first two periods and the last and a very appreciable increase in total length at the same time.
It was evident from the distribution of the measurements - especially the total lengths - that the last group was heterogeneous. For that reason a very late group was picked out of the material, namely 150 birds chosen at random from those trapped 19 - 21 September. Similarly a very early group was selected, namely 150 birds chosen at random from those trapped 27 - 28 August. (...)
The conclusions drawn from the preliminary analysis are further strengthened by this treatment. There is a remarkable conformity in bill-length between early and late birds. The frequency distribution of measurements in each group is close to normal, which indicates that the difference in bill-length between the sexes, known from museum studies
on the Dunlin, is not very pronounced in the present material of young birds. The wings of August birds are about 3 mm longer on the average than those of September birds (and this difference) is highly significant. Etcetera, etcetera.
CP: This is an old paper, an antique. What I like about it is the fact, that it is transparent; the conclusions can be checked, this is not
always the case when it comes to papers based on Ottenby material. The sampling intervals seem a little "forced", but there is no way telling if this also lies behind the "non-committal" of the conclusions. What everybody would like to see from Ottenby is large, coherent materials - moult, biometry - covering the whole of the migration period, without any kind of calendar compulsion or possible influence from measuring techniques.
Mascher, J. (1966): Weight variations in resting Dunlins (Calidris a. alpina) on autumn migration in Sweden. Bird-Banding 37: 1 - 34. This paper has a long summary, I choose to quote points 2, 4 and 5. Pdf version on the web.
2. As is clear from the recapture figures, the passage proceeds much faster early in the season than later. In 1963, only 14.5 per cent of the adults were retrapped as compared to nearly 30 per cent of the later-arriving juveniles. Very few adults stayed more than 2-3 days, whereas 18.3 per cent of all recaptured juveniles lingered more than 8 days. (...)
4. An increase in total weight of 0.50 gm per mm wing length was found in the juveniles. This is appreciably more than the figures applying to medium-sized and larger passerines. In adult Dunlins, a somewhat smaller increase amounting to 0.41 gm per mm wing length was found, but the difference is barely significant.
5. The lowest weight records obtained were probably near the fat-free weight of the subspecies C. a. alpina, which is likely to average about 34-35 gm. Some fat-free data on the larger sakhalina subspecies averaged about 5 gm more than the fat-free weight calculated for the corresponding wing length in C. a. alpina. The maximum fat deposition in Dunlins resting at Ledskär amounted to 20-25 gm fat or 40 per cent of total body weight, which is in accordance with
data published on passerine migrants.
Mascher, J. & V. Marcström (1976): Measures, weights, and lipid levels in migrating Dunlins Calidris a. alpina L. at the Ottenby Bird Observatory, South Sweden. Ornis Scand. 7: 49 - 59.
Measurements, weights, and lipid levels of 85 Dunlins collected during two autumn seasons at the Ottenby Bird Observatory in South Sweden were analyzed. Males had significantly shorter wings and bills, and lower body weights than females. Fat depots ranged from about 5 to 30 per cent of total weight an accounted for the major variations in body weight. No correlation was found between body size and lipid level. The water content expressed as a percentage of fat-free weight was virtually constant within each year sample, irrespective of body size and lipid level. Significant differences in fat-free dry weights and water content between the two year samples were found. A formula for calculation of fat stores from total weight and wing length is presented. The results are compared to other work on waders and passerines.
McCulloch, M. N. & N. A. Clark (1991): Habitat Utilisation by Dunlin on British Estuaries. BTO Research Report No. 86. BTO, Thetford.
McEwan, E. H. & P. M. Whitehead (1984): Seasonal changes in body weight and composition of Dunlin (Calidris alpina). Can. J. Zool. 62: 154 - 156.
McNeil, R. & F. Cadieux (1972): Numerical formulae to estimate flight range of some North American shorebirds from fresh weight and wing length. Bird-Banding 43: 107 - 113.
Meissner, W. (1998): Fat reserves in Dunlins Calidris alpina during autumn migration through Gulf of Gdansk. Orn. Svec. 8: 91 - 102.
To describe fat reserves in adult and juvenile Dunlins during autumn migration in the Gulf of Gdansk, multiple regression equations for estimating fat mass in Dunlins were
derived. The average fat level in a particular wave of migrants depends on many factors. Low amount of accumulated fat suggests that this species migrates along the southern Baltic in small steps, similarly to the rest of Europe. The interpretation of the results is difficult because at least two distinct migration routes cross the Gulf of Gdansk region. Dunlins starting their primary moult had lower fat index than birds in advanced stages of moult. The rate of fattening in Dunlin depends on the quality of the feeding place (higher in the sewage farm than in the river estuary). Birds which stayed longer in the feeding area had, on average, lower fat mass increments than those leaving Gulf of Gdansk after a short stay. Birds with low fat mass started putting on weight immediately, whereas "fat" birds lost weight at the beginning. Those results confirmed Mascher's (1966) hypothesis about differences in body mass change rate during the first day of stay in birds with low and high fat reserves. The level of free fatty acids in the blood appears to be a factor controlling this pattern. Differences in fat accumulation between Ottenby (southern Sweden) and Gulf of Gdansk are discussed.
CP: 426 out of 8443 = 5.0 % Dunlins caught at Rewa and 140 out of 1685 = 8.3 % at adjacent Jastarnia had scores 49 - 50 (i.e. complete wing). In all, 5.6 % of all adults passing the Rewa area had performed a complete moult on or near breeding-grounds, they migrated with fresh remiges. And these completely moulted adults accompany juveniles, in Poland till the catch is ended prematurely in late September, in the Sound area until the last migration waves in October. I do not expect anyone to suggest seriously, that the Polish birds had returned from moulting grounds in the Waddensea. (I had this suggestion in connection with late adults at Langenwerder). This note is saved here for reference.
Also note the remark: Data from birds retrapped in the Rewa region show that many are in active moult (unpublished data), as occurs on the Swedish coast (Holmgren et al. 1993). This is the same vague way of self-quotation as in Holmgren et al. 1993b! I have a question here: Catches reveal different stages of moult at Rewa - but what do retraps show? A score of adults has rested for more than a week. This material could be very important - but is it conclusive?
Meissner, W. & M. Skakuj (2009): Ageing and sexing the Dunlin Calidris alpina. WSGB 116: 35 -38.
CP: A sloppy paper that disgraces authors and referee. Meissner belongs to the authors using references as ornaments, he quotes in order to magnify himself, and often quotes contrary to his own conviction or experience. In contrast to Jadwiga Gromadzka he seldom quotes Russian workers, nor does he seem to have open channels to Gromadzka herself, there is a rift in Polish ornithology. As a person he reflects contemporary Poland, striving for recognition, a position in the world. His strong side is his access to a wealth of Polish field material - and i myself owe a debt of gratitude to him - but as a scientist he is conventional, commonplace, lacks courage. Both Meissner and Clark are well aware of the existence of the Dunlin website, and they both know that the material presented there outshines anything printed on the matter in Europe - in particular within the framework of the WSG - but they are too vain or too prejudiced to refer to it! The paper illustrates how the WSG has become a bloodless club for "internal admiration". I will concentrate my criticism on Meissner's quotation technique, which has annoyed me for quite some time now, and in order to restrict the polemics i will mention four initial point only:
1. Meissner tells us: Currently nine subspecies are recognized, which
differ in size and in the colour of the upperparts in breeding plumage (del Hoyo et af. 1996). Why are we fed with this information to some "Handbook of the Birds of the World" - as if these obscure handbooks have the essential or original thing to say about supspecific division in Dunlin? Why not e.g. Engelmoor and Rosselaar 1998, or some journal paper, which have much more to add on this point? I hate this type of vanity quotation, it's so meaningless.
2. Next line: there is evidence that shows that some birds may originate from as far east as
the Taimyr Peninsula, again a pompous and vague statement without the most modern and relevant reference. Why not for example Tomkovich, Lappo and Syroechkovskij (2000), a paper that lists the existing recoveries from Taimyr up till that year, and in a sense tells us: "non plus ultra"? I am often struck by the feeling that Meissner consequently gives the second or third best reference!
3. Meissner knows that there is a substantial late autumn migration of adult Dunlin in the Baltic, and he should know from Polish recoveries that the individual moult and migration strategy may shift between years (choice between the Black Sea and the Baltic, migration flight on unmoulted or moulted wing), still he prefers to quote himself out of the moult dilemma by referring to the nonsensical and catastrophic Holmgren papers: Some individuals start replacing primaries during incubation in June (Holmgren et al. 2001), while others begin replacing body feathers and inner primaries during migration, on moulting areas or on the wintering grounds. Primary moult is not usually arrested during migration (Holmgren et al. 1993). What has been written about moult based on Ottenby material is utterly confused and misleading; the orthodox Darwinist point of departure makes Holmgren et co-authors miss all relevant points. And Meissner himself, not corrected by the referee Nigel Clark, writes "arrested" where he by all likelihood intends to say "suspended", an old and recurring error by authors who are not at ease with moult materials and moult terminology.
4. When it comes to the time schedule of birds with "adult buff" coverts, Meissner is happy to quote himself: On the Polish Baltic coast these birds occur more numerously from mid-September, whereas in the Adriatic they appear from the beginning of September (Meissner et at. 2005). This is totally incomprehensible to me, since the first migrants with "adult buff" occur in the Öresund area from 10 July - a parallel to the regular migrations of Curlew Sandpipers from the Taimyr by the same time - and the culmination falls shortly after 1 August. There is a moult diagram, based exclusively on Dunlin with "adult buff" medians in the original moult paper, and there are pictures of birds with fresh adult buff medians from the end of July in the picture collection. I know from the visitors' addresses that readers from Meissner's and Clark's institutions have visited and studied my website, but obviously to little avail. I would like to forward as a hypothesis: Meissner and Clark are too vain or too prejudiced to quote from web material that could have improved and corrected this muddled, inferior paper. Their failure in turn also shames the Wader Study Group.
Meltofte, H. & J. Rabøl, (1977): Vejrets indflydelse på efterårstrækket af vadefugle ved Blåvandshuk, med et forsøg på en analyse af trækkets geografiske oprindelse. DOFT 71: 43-63.
Meltofte, H. & P. Lyngs, (1981): Spring migration of waders Charadrii at Blåvandshuk, Western Denmark, 1964-1977. DOFT 75: 23-30. Excerpt from the summary.
(...)In Limosa limosa and Calidris alpina, together with more usual occurrences of Calidris canutus, the main part of the movements pass south, and mainly in the morning hours. This migration is probably made up of birds passing the southern part of the North Sea on their way to the northern part of the Wadden Sea. Most birds are seen in southerly winds and low visibility, thus probably having drifted a little north during the passage.
In Haematopus ostralegus, Limosa lapponica and Calidris alpina two distinct peaks are seen during spring. It is concluded that these are made up of different populations. (...) In Limosa lapponica and Calidris alpina they may be populations having wintered in West Europe and West Africa, respectively, and which arrive in the Wadden Sea at different times, the African wintering population arriving later than the European wintering birds.
Meltofte, H. (1993): Vadefugletrækket gennem Danmark. DOFT 87: 1 - 180. Short excerpts of the Dunlin text are quoted here.
p. 66: It is not possible to separate the migration of European and Siberian birds, but as the migration culminates c1 week earlier in SW Finland, at Ottenby and S. Amager (Copenhagen, Sealand) than at Blåvand (W Jutland) (Fig. 23; Edelstam 1972, Kaukola & Lilja 1972), it is probable, that North European breeding birds migrate a little earlier
than Siberian. Wader migration at Blåvand generally has a higher share of Arctic populations than Baltic sites (Meltofte & Raböl 1977). And the ringing material from the Dutch Waddensea indicates, that European breeding birds to a higher extent migrate by way of the Baltic (Goede et al. 1990).
p. 70: During the culmination of juvenile migration, in September-October, some 250000 - 350000 Dunlin are regularly present in the Danish part of the Waddensea, and occurrances exceeding 400000 have been noted twice. These are very high numbers compared with the remaining parts of the Waddensea, and the same applies to spring, The maximum number in Schleswig-Holstein is 300000, in Niedersachsen 290000, in Holland 274000 (Smit & Wolff 1981, Zegers & Kwint 1992, J. Blew and H.-U. Rösner in litt.) In other parts of Denmark some 40 - 50000 birds are resting during the same period.
Meltofte, H., J. Blew, J. Frikke, H.-U. Rösner & C. J. Smit (1994): Numbers and distribution of waterbirds in the Wadden Sea. Results and evaluation of 36 simultaneous counts in the Dutch-German-Danish Wadden Sea 1980-1991. IWRB Publication 34, WSG Bulletin 74, Special issue.
(from text) Our mid-winter counts have yielded totals of between 131,000 and 258,000 during mild winters. Of these, up to 210,000 have actually been counted. Considerably less Dunlins remain during severe winters, when we recorded between 23,400
and 62,200. In mild winters, the Dunlins are surprisingly evenly distributed throughout most of the Wadden Sea, where they predominantly feed on silty flats (Ens et al. 1993). In severe winters, the Danish, German, and eastern parts of the Dutch Wadden Sea are largely deserted. In January 1992 a record 78,000 Dunlins were found in the Schleswig-Holstein Wadden Sea (Rösner unpubl.).
In spring, large numbers of Dunlins start to move into the Wadden Sea from late February onwards. These are birds that have wintered further west and south in Europe, which go to the Wadden Sea to moult into breeding plumage and build up body reserves for the onward migration. Numbers increase in most areas during March and April, until a new influx of birds apparently takes place in early May. There are indications that the Dunlins arriving in March and April are European sub-arctic breeders, while those passing in May breed in Siberia (Goede et al. 1990, Meltofte 1993). Acording to our counts, more than 400,000 Dunlins may be present in the Wadden Sea already by March. Numbers increase to between 804,000 and 1,120,000 during our best counts in the first half of May, when birds from the whole breeding range are supposed to be present. Of these up to 1,046,000 Dunlins were actually counted. With 50,000-100,000 Dunlins staging in other parts of Denmark and 15,000-35,000 in the Dutch Delta (Meininger & van Haperen 1988, Meininger et al. 1994), this means that up to about 90 % of the West European/West Mediterranean alpina Dunlins could be present in the Wadden Sea countries at this time. As some hundreds of thousands may fly north via South-east Europe and the Black Sea in spring (Meltofte 1991, 1993), this may merely point to an underestimation of the population, however. Wadden Sea numbers decrease during mid and late May, when first the European sub-arctic breeders and then the arctic breeders leave for their breeding grounds. (...)
Ming, S. & L. Jianjian (1992): The dynamics of body composition of overwintering Dunlin Calidris alpina sakhalina. Wader Study Group Bull. 64: 35-36.
Minton, C.D.T. (1975): Waders of the Wash - ringing and biometric studies. Rep. Sci. Study Group of the Wash Water Storage Scheme.
Morrison, R. I. G, Gill Jr., R. E., Harrington, B. A., Skagen, S., Page, G. W., Gratto-Trevor, C. L. & S. M. Haig. (2001): Estimates of shorebird populations in North America. Occasional Paper No. 104, Canadian Wildlife Service, Ottawa, Ontario. 64 pp.
Mouritsen, K. N. (1992): Predator avoidance in night-feeding Dunlins Calidris alpina: a matter of concealment. Orn. Scand. 23: 195 - 198.
The anti-predator behaviour of night-feeding Dunlins Calidris alpina was studied on a tidal flat in the Danish Wadden Sea. The observations indicated that Dunlins at night depress vocalization compared with day-feeding birds. Moreover, when Dunlins were approached by a raptor during day-time almost all took flight. In contrast, when Dunlins were disturbed at night only about 60 % took flight, while most of the remaining birds froze. It is suggested that depressed vocalization and freezing at night are means to escape detection by owls. How the behavioural dichotomy (freezing and escape) during nocturnal disturbance is accomplished and how it affects the spacing behaviour of night-feeding Dunlins are discussed.
Mouritsen, K. N. & K. T. Jensen (1992): Choice of microhabitat in tactile foraging Dunlins Calidris alpina: the importance of sediment penetrability. Mar. Ecol. Prog. Ser. 85: 1 - 8.
Tactile-searching dunlins Calidris alpina fed selectively in small-scale depressions on an intertidal mudflat in the Danish Wadden Sea. This choice of microhabitat could be related to higher sediment penetrability in depressions compared with the surrounding flats, allowing the peck depth to be doubled. A model is presented describing the probability of dunlins detecting the predominant prey item Hydrobia ulvae as a function of peck depth. The model predicts that the increased peck depth in depressions would improve foraging success 4-fold. It is suggested that the presence of depression and the accompanying increase in sediment penetrability not only account for the selection of microhabitat but also affect the distribution of dunlins on a larger spatial scale.
Mouritsen, K. N. (1993): Diurnal and nocturnal prey detection by Dunlins Calidris alpina.. Bird Study 40: 212 - 215.
Mouritsen, K. N. (1994): Day and night feeding in Dunlins Calidris alpina: choice of habitat, foraging technique and prey. J. Avian Biol.. 25: 55 - 62.
The diurnal and nocturnal foraging behaviour of Dunlins Calidris alpina was investigated during their autumn migration in the Danish Wadden Sea. Dunlins fed regularly both day and night. However, they tended to utilize different habitats during daytime and night-time, with relatively more birds aggregating on soft sediment containing high densities of Corophium volutator at night. Pecking was the dominant foraging technique during the daytime, whereas probing was the preferred technique at night. Dropping analysis revealed quantitative differences between the birds' diurnal and nocturnal diets. It is proposed that nocturnal foraging may be important for restoring fat deposits in migrating birds.
Mullié, W. C. & P. L. Meininger (1983): Waterbird trapping and hunting in Lake Manzala, Egypt, with an outline of its economic significance. Biol. Cons. 27: 23 - 43.
In the winters of 1978/79 and 1979/80, and in September and October 1980, the authors investigated the trapping and hunting of waterbirds in Lake Manzala (Egypt). It has been calculated that 98 000-162 000 waterbirds are killed annually. The number of people practising these activities is estimated at less than 2000 in a population of 35 000-40 000 fishermen. The majority of the birds are, however, taken by less than 100 men. Compared with 1930 about 30-50% fewer duck and coot are sold. This decrease is mainly caused by the decrease in numbers of pochard and tufted duck. Hunting pressure on waders was found to be extremely high. The contribution of these activities to the regional economy is reviewed and found to be insignificant. A number of conservation measures are recommended.
Müller, S. (1985): Bemerkenswerte avifaunistische Beobachtungen aus Mecklenburg. Orn. Rundbr. Mecklenb. 28: 68-96.
Nebel, S., Jackson, D. L. & R. W. Elner (2005): Functional association of bill morphology and foraging behaviour in calidrid sandpipers. An. Biol. 55: 235 - 243.
Nehls, G. & R. Tiedemann (1972): What determines the densities of feeding birds on tidal flats? A case study on dunlin, Calidris alpina, in the Wadden Sea. Netherlands J. Sea Res. 31: 375 - 384.
The tidal and seasonal pattern of habitat utilization by dunlin was studied in a tidal-flat area in a shallow bay called Königshafen, island of Sylt, by counting the number of dunlins on marked plots at 10-min intervals over whole tidal cycles. Sediment type, tidal elevation, and seasonal changes in food choice were found to influence the feeding densities of dunlin irrespective of total numbers present in the area. Densities of dunlin were generally highest on low muddy substrates. A preference for high sandy substrates was found in late summer. The tidal pattern of habitat utilization differed between areas. In preferred areas dunlin stayed during the whole emersion period. Other areas were only used by following the moving tide line. Seasonal changes in habitat utilization were apparently triggered by changes in food choice. In spring dunlin fed almost exclusively on polychaetes. In late summer a relatively high proportion of shrimps, Crangon crangon, was found in the diet of dunlins. The preference for shrimps may force the birds to stay away from the tide line, where the shrimps can escape into deeper waters. It is recommended that studies on habitat utilization on tidal flats should consider the tidal behaviour of the target species, as single low-tide counts may not give valid results.
Nieboer, E. (1972): Preliminary notes on the primary moult in Dunlins Calidris alpina. Ardea 60: 112-119. A Dutch pioneering paper, fieldwork at Schiermonnikoog in 1968 and 69, no summary.
Norton, D. W. (1971): Two Soviet recoveries of Dunlins banded at Point Barrow, Alaska. Auk 88: 927.
Two Soviet recoveries of Dunlins banded at Point Barrow, Alaska. MacLean and Holmes (Auk, this issue, p. 893) concluded on morphological and behavioral grounds that Dunlins (Calidris alpina) breeding in Alaska represent two distinct races: C. a. pacifica of western Alaska and the American Pacific coast, and C. a. sakhalina of northern Alaska, Siberia, the Yellow Sea, and the Sea of Japan. They hypothesize that birds breeding in northern Alaska migrate across the Bering Straits to wintering grounds on the Asian Pacific coast. This hypothesis is confirmed by Soviet recoveries of two Dunlins that I banded as breeding adults on nests within 8 km of Point Barrow (71° 18' N, 156° 47' W). One bird (U.S.F.&W.S. No. 72-191708) was banded on 15 July 1968 and shot on 28 October 1969 at Lazarev Cape, Nikkolaev District, USSR (52° 13' N, 141° 28' E). The second (U.S.F.&W.S. No. 67-193801) was banded on 19 June 1969 and shot on 17 October 1969 on Sakhalin Island, near Starodubsk, Dolinskii District, USSR (47° 27' N, 142° 49' E). (...)
Nörrevang, A. (1955): Rylens (Calidris alpina (L.)) traek i Nordeuropa. DOFT 49: 18 - 49.
(...)No doubt some of the Dunlins observed in southern Sweden - Norway and in Denmark come from northern Scandinavia, but studies at Jæren indicate that many of the birds come from northern Russia and Siberia. The Taymyr peninsula probably acts as a sort of migratory divide. One bird with bill 38 mm no doubt comes from Western Siberia.
Mr HOLGER HOLGERSEN tells (in litt.) that a bird ringed at Jæren on Sept. 22nd, 1950, was recovered from the Yamal Peninsula in northwestern Siberia in June 1951.
The populations of Russia and Siberia must migrate WSW along the northern coast of Russia. However, some birds probably go due south (inland migration has been observed) but they will hardly touch Europe. At Rossitten there were large birds, too, probably coming from West Siberia also. These birds must have passed the Onega-Ladoga lake-district (PALMÉN'S migration route).
The Öland birds may have come from the Estonian islands of Hiiumaa and Saaremaa as the migration is partly west-bound. No doubt these birds have come there by the same route as those migrating along the southern limits of the Baltic.
South-directed birds (transversing the inland of Central Europe): From Rossitten 33.3 per cent, from Öland 9.3 per cent and from Amager 5.0 per cent. Birds from Jæren going south will be led along the western coast of Jutland. Still, one bird was recovered in Zealand(...).
No strong migration should be expected at Jæren, but nevertheless it is very strong. Some of the birds cross the North Sea, but many of them go straight south and are recovered in Denmark (10.6 per cent). There may be two causes for this, viz.: 1. North-Scandinavian birds going south cross the migration route of eastern birds going southwest. 2. There is a regular deviation of the birds going SW so that they for some reason are pushed northwards. From Jæren they either continue in the old migration-direction or they try to find again the old migration route by going S.
It speaks for the second suggestion, that ten birds ringed at Jæren were recovered at Öland in later years, and two recorded at Amager. Only one bird ringed at Öland was recovered at Jæren in a later season.
OAG Münster. (1976): Zur Biometrie des Alpenstrandläufers (Calidris alpina) in den Rieselfeldern Münster. Die Vogelwarte 28: 278 - 293. (Biometry of Dunlins in the Sewage Farms of Münster.)
1. From 1969 on to 1975 331 Dunlins were caught and measured in the sewage farms of Münster, 13 of them in the home-migration period. In the off-migration period only 12 adults were ringed. Therefore this study mainly deals with juvenile birds.
2. The frequency distribution of wing lengths corresponds approximately to a normal distribution, in contrast to the bimodal distribution of bill lengths. According to these measurements by far the greatest part of the birds caught belongs to the nominate race, fewer individuals to the race C. alpina schinzii and very few probably to C. alpina sakhalina (about 3 cases).
3. The pentade mean values of wing and bill lengths show a distinct downward trend throughout September and October.
4. The standardized weights yield a normal distribution; the mean weight is quite high in comparison to dates from literature. The pentade mean values of weight do not demonstrate clear changes throughout the off-migration period. The changes of weights of recaptured Dunlins scatter very much and do not show a trend.
5. Correlations between various measurements are statistically highly significant.
6. 20 % of juvenile Dunlins were found moulting body feathers and wing coverts.
Page, G. W. (1974): Age, sex, molt and migration of Dunlins at Bolinas Lagoon. West. Birds 5: 1 - 12.
Page, G. W., Stenzel, L. E. & J. E. Kjelmyr. (1999): Overview of Shorebird Abundance and Distribution in Wetlands of the Pacific Coast of the Contiguous United States. The Condor 101: 461 - 471. Internet version of this paper
We coordinated censuses from April 1988 to April 1995 to obtain an overview of shorebird abundance and distribution in Pacific Coast wetlands of the contiguous United States. We attempted to acquire at least 3 years of data for all major wetlands from counts within a short time window each fall, winter, and spring. Fourteen abundant, 8 moderately abundant, and 21 rare-to-uncommon species were recorded. For temperate-zone breeders, peak periods of abundance were fall or winter and, when discernible for arctic breeders, mostly fall or spring. Arctic breeders were relatively more abundant than temperate-zone breeders in Oregon and Washington wetlands. All five of the most abundant temperate breeders were limited primarily to California wetlands in all seasons. Only for Western Sandpiper (Calidris mauri) and Dunlin (C. alpina) did the estimated total individuals present simultaneously in all wetlands exceed 100,000. Fifty-six of 66 sites surveyed had at least four counts and at least 100 shorebirds on one or more counts; 38 of the 56 sites held at least 1% of 1 of 13 key species during at least one season. San Francisco Bay accounted for 24-96% of the estimated totals for key species; Grays Harbor, Willapa Bay, Humboldt Bay, Tomales Bay,, Point Reyes Esteros, Bolinas Lagoon, Elkhorn Slough, Morro Bay, Mugu Lagoon, Bolsa Chica, Mission Bay, and San Diego Bay held at least 1% of at least half the key species in at least one season. The usefulness of five criteria for selecting key wetlands for shorebird conservation are examined and potential threats are discussed.
Pettersson, J. (1994): Ottenby fågelstation 1993, in: SOF 1994.
Fågelåret 1993. Stockholm.
Perttula, H. (1990): (transl.:) Breeding areas of Southern Dunlin in Finland and restoration of habitat. Lintumies 25: 11 - 15.
Pienkowski, M. W. & W. J. A. Dick (1975): The migration and wintering of Dunlin Calidris alpina in north-west Africa. Orn. Scand. 6: 151 - 167.
The numbers of Dunlins present during the year on the coasts of north-west Africa are summarised. Information on timing of migration, ringing recoveries, and analysis of bill lengths is used to determine the geographical origins of these birds. Most individuals are from the breeding populations in southern Scandinavia, western Europe, and Iceland, so that Morocco and Mauritania are of unique importance to these populations in the non-breeding season. There is some overlap in Morocco with populations from the northern Eurasian breeding grounds whose main wintering area is further north in Western Europe. The north-west African birds migrate in short flights without putting on large fat reserves. Many birds moult their primary feathers during migration.
Pienkowski, M. W. (1976): Recurrence of waders on autumn migration at sites in Morocco. Vogelwarte 28: 293 - 297.
Pienkowski, M. W., Knight, P. J., Stanyard, D. J. & F. B. Argyle (1976): The primary moult of waders on the Atlantic coast of Morocco. Ibis 118: 347 - 365.
(...)Similar rates of primary feather replacement relative to specific moult duration were observed in all species for which information was available. Comparisons between species and with published studies showed that variations in rate of moulting between species and between different geographical populations of the same species were largely due to differences in feather growth rate rather than in the number of primaries concurrently in growth. Variations in rate between individuals of the same population were achieved, at least in the first part of moult, by differences in feather dropping rate resulting in differences in the numbers of primaries growing concurrently.
(...)Most Redshank and possibly Dunlin migrated in active wing moult.
Pienkowski, M. W., Lloyd, C. S. & C. D. T. Minton (1979): Seasonal and migrational weight changes in Dunlins. Bird Study 26: 134 - 148.
In eastern England, Dunlin weights peak in December. Is this because food is abundant then, or an 'insurance' against cold weather to come? Such early winter weight peaks do not occur in south-western Britain and the implications of this are discussed.
Pienkowski, M. W. & P. R. Evans (1984): Migratory behaviour of shorebirds in the western Palearctic, pp. 73 - 123 in: J. Burger & B. L. Olla: Behavior of Marine Animals. Vol. 6, Shorebirds: Migration and foraging behavior. Plenum Press, New York.
Piersma T. & N. E. van Brederode (1990): The estimation of fat reserves in coastal waders before their departure from Nortwest Africa in spring. Ardea 78: 221 - 236.
To derive realistic equations for evaluating the fat loads of waders before their departure from NW Africa in spring, we have analysed samples of waders inadvertedly killed during catching operations in Morocco, Tunisia and Mauritania. We studied the relationships between body and fat mass and structural size variables. Part of the original variation in body mass was attributable to a constant relative water loss between capture and first weighing, and body mass values used in the consequent analyses were corrected accordingly. In the four species for which large samples were available (Knot, Little Stint, Dunlin and Redshank), linear regression of fat mass on body mass indicated that 50 - 60 % of the differences in individual body mass is due to differences in the total fat mass. In all four species wing length correlated well with lean mass, suggesting that this dimension is generally a better structural variable than total head, bill and tarsus plus toe length. Only in Dunlins, bill length correlated best with lean mass. Multiple regressions with fat mass as the dependent variable and body mass and structural size variables as independent variables, showed that only those dimensions which correlated with lean mass, contributed significantly to the explained variance in fat mass in addition to body mass. An alternative regression model in which body mass was estimated from fat mass and structural size variables and then reformulated, did not lead to improved predictive equations. The suggested equations to estimate fat mass in individual Knots, Little Stints, Dunlins and Redshanks allows the estimation of fat mass of the heaviest birds with an accuracy of ca 30 %, but with a much lower accuracy in light birds (all estimated values within 100 % from the true value).
Pitelka, F. A., Holmes, R. T. & S. F. Maclean (1974): Ecology and Evolution of Social Organization in Arctic Sandpipers. Amer. Zool. 14: 185 - 204.
A comparative analysis of sandpiper social systems on arctic and subarctic breeding grounds (24 species in the family Scolopacidae, subfamily Calidridinae) shows four major patterns. In a majority of the species (15), populations are dispersed through a strongly developed territorial system, with strong monogamous pair bonds and only minor yearly fluctuations in numbers. The second pattern is seen in three species in which the female of a pair may lay two sets of eggs in quick succession, one for each member of the pair to incubate. This opens opportunities for facultative polygyny or polyandry ('serial polygamy') and for the evolutionary weakening of the strong pair bond seen in the first pattern. The third and fourth patterns are those of polygyny (three species) and promiscuity (three species). These six species show clumped dispersions; their year-to-year fluctuations tend to be strong; the males defend compressible, often small, territories; and high densities can occur locally. It is suggested that the pattern of overdispersion and monogamy represents a conservative mode of adapting to high-latitude environments, while the pattern of clumped dispersion with polygyny or promiscuity represents an opportunistic mode in that the birds are concentrated into breeding areas where and when weather, food, and/or some other environmental factors are particularly favorable. Apparently falling evolutionarily between these two basic patterns are several species conservative in their life-styles, but polygamous at least occasionally and showing some features of opportunism. There is thus a striking diversity of social systems in calidridine sandpipers, that is, in the styles of habitat exploitation they have evolved in the arctic and subarctic habitats to which their breeding is confined. A graphic model suggesting paths of evolutionary development and of interplay among factors considered critical in the evolution of these systems is proposed.
Prater, A. J., Marchant, J. H. & J. Vuorinen (1977): Guide to the Identification and ageing of Holarctic Waders. BTO Guide 17, Tring 1977.
Rehfisch, M., Austin, G. & A. Musgrove (2003): Wintering waders in decline. Bird Populations 7: 162 - 165. pdf version on the web.
Remisiewicz, M. (1996): Influence of weather conditions on the autumn migration of Dunlin (Calidris alpina) at the southern Baltic coast. The Ring 18: 73 - 88.
Reneerkens, J., Piersma, T., Jukema, J., de Goeij, P., Bol, A. & H. Meltofte (2005): Sex-ratio and body size of sandpiper chicks at Zackenberg, north-east Greenland in 2003. WSGB 106: 12 - 16. Internet version of this paper.
There is growing evidence that female birds may adaptively bias the sex ratio of their young as a function of environmental conditions. Data on brood sex ratio in shorebirds are scarce, however. In this study we report the brood sex ratios and morphometrics of Arctic sandpipers. Sex was determined in 13–64 chicks of Sanderling Calidris alba, Red Knot Calidris canutus islandica, Dunlin Calidris alpina arctica, and Ruddy Turnstone Arenaria interpres in NE Greenland during the 2003 breeding season. Brood sex ratios were biased significantly towards males in Dunlin and Ruddy Turnstone, but in Dunlin this bias disappeared in chicks older than two days. There was a non-significant bias towards females in Sanderling and Red Knot. Only for bill length in Dunlin hatchlings, there were significant differences between males and females. Surprisingly, in contrast to their parents, male chicks had longer bills than female chicks.
Roos, G. (1962): Vinterfåglar på Falsterbonäset. Fauna och Flora 57: 249 - 273.
Roos, G. (1984): Flyttning, övervintring och livslängd hos fåglar ringmärkta vid Falsterbo (1947-1980). Anser, Supplement 13. Lund 1984.
Rose, P. M., & D. A. Scott. (1997): Waterfowl Population Estimates - Second Edition. Wetlands International Publ. 44, Wageningen, The Netherlands.
Ruiz, G. M., Connors, P. G. Griffin, S. E. & F. A. Pitelka (1989): Structure of a wintering Dunlin population. Condor 91: 562 - 570. Internet version of this paper
We have documented structure on two different scales for the Dunlin (Calidris alpinaj ponulation wintering at Bodega Bay. California in 1986-1987. Within a night roost significantly more juvenile birds were captured at the center vs. periphery between October and December. In addition, there was a significant difference in the mean size of birds among areas of the roost during November, with birds at the center being largest. Structure also developed during the winter on a scale which separated the entire population at Bodega Harbor into two groups. In late winter, large numbers of Dunlins left the area late in the day and returned in early morning, apparently roosting elsewhere. As a result, the number of Dunlins at the night roost declined in winter much more than the daytime population size at Bodega Bay. These roughly crepuscular movements were not evident earlier, in the fall, and did not correspond closely to tidal cycles. The resultant fragmentation of the population into "resident" and "mobile" groups was reflected in physiological differences between groups. Those birds which remained in the harbor day and night (residents) weighed less, had lower amounts of body fat, and were delayed in molt schedule in March relative to (mobile) birds which left at night. While the ecological significance of structure on both scales remains unknown, evidence from this and previous studies suggests that it may be a relatively common phenomenon with important implications for studies of avian populations.
Rösner, H.-U. (1990): Sind Zugmuster und Rastplatzansiedlung des Alpenstrandläufers (Calidris alpina alpina) abhängig vom Alter? J. Orn. 121 - 139. (Are there age dependent differences in migration patterns and choice of resting sites in Dunlin Calidris alpina alpina?)
The Dunlin is the most numerous wader species in the whole Wadden Sea. It uses the area mainly for fattening in spring and for moulting in late summer. In the Wadden Sea a very
strong site fidelity in adults was found. The same is true in the British estuaries, which are the main winter quarters. This allows the adults to develop a good knowledge of local conditions in the comparatively few areas used. In contrast to the adults, juveniles on autumn migration stop at more places and stay longer at each. They also use sites where only a very few adults are seen. Results of catching and counting in the Wadden Sea suggest that competition between adults and juveniles influences the dispersion of juveniles. To explain these phenomena, a hypothesis on migration patterns is presented. It is suggested that juveniles start their first autumn migration by taking only a rough general direction without aiming to reach particular resting sites. They probably find these by trial and error, visiting only suitable sites again in the following years. Therefore juvenile Dunlins should discover newly arisen sites very quickly and may even fill them up. They should not stay at those sites which decrease in quality, so these sites will loose numbers in spite of high site fidelity of adults. The hypothesis could also help to explain results which are so far assumed to be caused by the occurrence of different subpopulations.
CP:
This is a speculative paper, and I think I see the "epistemological" elements of its structure: a thought construct reified into reality. Under normal circumstances this course might be quite legitimate, but if the justification fails - if only to some extent - the speculator is in trouble. He must make exceptions, and these exceptions start a landslide. Rösner's model holds as long as it is not discussed.
Rösner, H.-U. (1997): Strategien von Zug und Rast des Alpenstrandläufers (Calidris alpina) im Wattenmeer und auf dem Ostatlantischen Zugweg. Aachen 1997. (Strategies of staging and migration of Dunlin in the Wadden Sea and along the East-Atlantic Flyway).
2. In the Wadden Sea, Dunlins are the most abundant bird species. Reaching counts of at least 1.2 million, almost all individuals of the West European wintering population can occur here at the same time. In the Schleswig-Holstein part of the Wadden Sea (SHW), numbers up to 600,000 were reached. Compared to other species, Dunlins are spread evenly across the SHW. They are present year-round, reaching their highest numbers from August to October and in April/May and very low numbers in June. During normal winters 10-20 % of the population are present in the SHW, during ice winters 2-4 %.
3. Among the staging areas, short-term and long-term can be distinguished. Along the Baltic coast there are numerous short-term staging areas. The waves of migration observed correspond well with the seasonal phenology in the long-term staging area SHW. Ringing recoveries also show that a large proportion of the SHW Dunlin regularly migrate along the Baltic coast.
4. The coasts of Great Britain and Ireland are the most important wintering area for SHW Dunlins. The south-western Wadden Sea, the Rhine Delta and the French and Portuguese Atlantic coast are also visited. Only a few individuals reach the Mediterranean Flyway and, possibly, Africa.
5. The breeding origin of SHW Dunlins includes mainly the tundra areas from northern Scandinavia to the Yamal Peninsula or just east of it. Birds from Taimyr do not, or only exceptionally, reach the SHW. A considerable fraction of the small Baltic breeding population also stages in the SHW. There is no
indication for birds of Nearctic origin. These results were reached mainly by colour-ringing on the breeding grounds; morphometric and genetic studies added to the picture.
6. Dunlins are highly site-faithful not only to breeding areas but also to their natal areas and to staging areas. SHW birds are, over many years, observed almost exclusively in the same staging areas; only few also visit other areas within the Wadden Sea.
7. Juveniles leave the breeding area later than adults and use partially different migration routes and short-term stopover areas. Even in the long-term staging area they initially hardly mix with adults and, even months later, still show a different distribution from that of the adults. This can be explained mainly by lack of experience, especially concerning predators. An effective mechanism for displacement of juveniles by adults could not be found. Proportions of juveniles are larger in the south-western than in the north-eastern Wadden Sea, probably because of differences in migration routes.
8. The characteristic features of juvenile migration hold one key to understanding the migration system and patterns of use of staging areas in Dunlin. Newly emerging areas can be settled quickly by juveniles. At the same time, areas with high hunting pressure (such as, perhaps, France) can act as a sink for juveniles.
9. By combining juvenile data from many short- and long-term staging areas, an index for the population-wide annual breeding success since 1948 is created. It shows a weak three-year
cycle and some correlations with the breeding success of other arctic-breeding bird species. Fluctuations in Dunlin breeding success are smaller than in other species, probably because of the wide range and less extreme breeding conditions of Dunlin.
10. For the period since 1970, data from numerous areas are combined to a 'flyway index' for the western European wintering population, which numbers from 0.9 to 1.5 million birds.
Periods of stable or increasing population numbers were interrupted by a ten-year period of low numbers. Unusually high mortality in the breeding areas in some years, fluctuation in production of young and ice winters majorly influenced the population development. The general increase in numbers probably started already before 1970, following very low population levels due to hunting mortality in the first half of this century.
11. On a large spatial scale, birds from diferent breeding areas are separated according to their migration times and routes. On a smaller scale, e.g. within the Wadden Sea, the characteristics of juvenile migration largely preclude a spatial separation of birds of different breeding origin. The temporally separate migration of Baltic birds is an exception here. The birds of northern breeding origin mix to a large extent; their timing of spring migration varies gradually according to the onset of breeding which varies by about one month across the climatic zones of the breeding area.
12. Within the range of the species, different life history strategies can be found. Birds breeding in the Baltic, Great Britain and Ireland tend to be limited by breeding habitat and have
abundant survival habitat, whereas the opposite is true for birds from Northern Scandinavia, western and eastern Siberia and northern Alaska.
13. At least in the past, the size of the western European wintering population was determined by hunting. The limiting factors at present are less certain, nor is it clear whether the long-term increase in population numbers is still continuing. On the West Pacific and Mediterranean Flyway, hunting is probably threatening populations at present; on the East Atlantic Flyway, primarily the very small breeding populations are endangered. For the future, an 'integrated population monitoring' of arctic waders is proposed; this is explained for the example of Dunlin on the East-Atlantic Flyway.
Sanzenbacher, P. M. & S. M. Haig (2002): Residency and Movement Patterns of Wintering Dunlin in the Willamette Valley of Oregon. The Condor 104: 271 - 280.
In the winters of 1998-1999 and 1999-2000, we tracked 67 radio-marked Dunlin (Calidris alpina) throughout the complex agricultural landscape of the Willamette Valley of Oregon. Individual birds were tracked across 8-week sampling periods and indicated a high degree of regional fidelity throughout the three winter sampling periods. Birds exhibited varied degrees of fidelity to specific wetland sites and were detected at an average of nine different sites. Distances traveled within the region were extensive and greatest during late winter. Females ranged farther from capture sites than males, and movement from capture sites for all birds was greatest during late winter. Mean home-range size (95% minimum convex polygons) of birds was 258.2 &plusmin; 44.8 km2 (SE) and was greatest during late winter. Diurnal roosts were identified as centers of activities and daily movements were most pronounced during crepuscular periods. These data represent the most extensive documentation of winter movements for a shorebird at an inland site. Findings indicate Dunlin were winter residents, and extensive local movements suggest a high degree of functional connectivity of habitats.
CP: Oregon lies south of Washington on the west coast, the subspecies involved should be pacifica.
Saurola, P. (1980): Recoveries of Calidris species ringed in Finland. (in Finnish) Lintumies 15: 146 - 153.
Senner, S. E., West, G. C. & D. W. Norton (1981): The spring migration of western sandpipers and dunlins in southcentral Alaska: numbers, timing, and sex ratios. J. Field Ornithol. 52: 271 - 284. Internet version of this paper.
Little is known about the migration of Dunlins and Western Sandpipers between the Fraser River Delta, British Columbia and the Copper and Bering rivers delta system (C-BRD). Censuses of transects and central population estimates at Hartney Bay, within the C-BRD system, show that these two species constitute about 95 % of all shorebird species using intertidal habitats. The bulk of migration at Hartney Bay occurs between 30 April and 15 May, with peak numbers occurring between 2 and 10 May. Throughout the C-BRD system, male Western Sandpipers predominate early in migration, while this phenomenon was not observed with Dunlins. Sightings of color-marked Western Sandpipers at Kanak Island suggest lengths of stay of 1 to 2 days, while marked individuals sighted at Hartney Bay remained for intervals of 2-6 days.
Large numbers of Western Sandpipers, far outnumbering Dunlins, were recorded at Kachemak Bay in lower Cook Inlet. These data are consistent with the hypothesis that Western Sandpipers, unlike Dunlins, need to stop at intermediary sites such as Kachemak Bay while en route between the C-BRD system and western Alaska breeding grounds (Senner 1979). However, we were unable to confirm this hypothesis because Western Sandpipers collected in Kachemak Bay had body measurements distinct from specimens collected in the C-BRD system. Whether the Western Sandpipers collected at Kachemak Bay and on the Chukchi Sea coast have breeding or wintering areas different from those of individuals which use the C-BRD system needs further investigation. Migrant Dunlins collected on the Chukchi Sea coast probably represent the subspecies which winters in Asia and breeds in Arctic Alaska.
The C-BRD system and Kachemak Bay stand out as "habitat islands" on the North Pacific coast and attract large numbers of migrating shorebirds. Studies considering the ways in which Western Sandpipers and Dunlins exploit these limited wetland habitats are needed fo fully evaluate the significance of the C-BRD system and Kachemak Bay in their annual cycles.
Serra L., Baccetti N., Cherubini G. & M. Zenatello (1998): Migration and moult of Dunlin Calidris alpina wintering in the central Mediterranean. Bird Study 45: 205 - 218. Internet version of this paper.
Dunlin migration in northeast Italy is described. An attempt to identify the main routes and staging areas used by birds wintering in the central Mediterranean is presented. The results of monthly counts from 1990-1995 revealed that the bulk of the population occupied the wintering area in October and left for the breeding grounds in April and May. The analysis of 342 Italian recoveries of foreign ringed birds showed that 65% were ringed during post-breeding migration through the Baltic Sea, whereas just a few birds had been ringed in western Europe. First-year birds arrived in autumn with a single migratory wave, peaking in October. Two categories of adults were identified during post-breeding migration: birds which directly reached Italian wintering sites and birds which arrived after they had suspended their migration for moulting: the Azov/Black Sea wetlands are suggested as possible moulting areas. Out of 2444 adults and 1627 first-years ringed between 1989 and 1996 at our study area, we obtained a total of 42 recoveries abroad and evidence of direct links between Azov/Black Sea and N Adriatic wetlands, both during autumn and spring migrations. Primary moult was observed only in adults arriving early, the second migratory wave being composed of moulted birds. Locally moulting adults adopted a moult strategy characterized by high raggedness scores, typical of resident moulters. Body mass was not affected by primary moult stage or intensity, winter mass values being reached two weeks after the average date of primary moult completion.
CP: I am inclined to put a death's-head in front of this paper; the editors of Bird Study have failed in their support. It's relatively new, and still hampered by the anecdotal or mythical knowledge surrounding Dunlin migration in the Baltic, and it is filled with errors, caused by quotation from uninformed sources like Greenwood 1983 and Holmgren et al. 1993a. There are two scores of similar, misleading quotations; Brenning 1987, 1989 might have illuminated the authors a little. So, a warning for the uncritical use of references in this paper! When it comes to the value of the Italian empirics per se i'm still not sure, i want to compare with what might emerge in some future.
Shepherd, P.C.F. et al. (2001): Sex ratios of Dunlin wintering at two latitudes on the Pacific Coast. Condor 103: 352 - 360.
Shepherd, P. C. F., Evans Ogden, L. J. & D. B. Lank (2003): Integrating marine and terrestrial habitats in shorebird conservation planning. WSG Bull. 100: 40 - 42.
Our studies in the Fraser River Delta, British Columbia, Canada, show that shorebirds that normally feed in the intertidal zone by day make greater use of terrestrial habitats for foraging than had previously been supposed, especially at night. We highlight the importance of shorebird ecologists extending their studies to evaluate fully the use of non-marine habitats and the significance of night-feeding. We outline the techniques that can be used to monitor habitat use and foraging strategies on a 24-hour day basis. We also draw attention to the importance of passing the results of such studies to land-use planners so that they can include key terrestrial habitats in management plans for coastal wetland sites.
Shepherd, P. C. F. & D. B. Lank (2004): Marine and agricultural habitat preferences of Dunlin wintering in British Columbia. J. Wildlife Man. 68: 61 - 73.
We examined winter habitat preferences of individual dunlin (Calidris alpina) in the Fraser River delta, British Columbia, Canada, adjacent to agricultural land near an area of dense and increasing human settlement. We used radiotelemetry and compositional analysis to quantify and describe dunlin habitat selection at 2 scales (regional and local) throughout the 24-hr day and daily tidal cycles. We tested for differences between sex and age classes, and among birds captured at different sites. Patterns of habitat preference differed between sexes and among dunlin from different sites in the delta, but we detected no difference between age classes. We ranked habitat types in order of dunlin preference and tested for significant differences among habitat ranks. Dunlin showed a significant preference for tidally influenced marine habitats at both scales and throughout the study area. However, most individuals (>80%) also used terrestrial habitats, usually during high tide and primarily at night. The role of terrestrial habitats in the ecology of Fraser River delta dunlin previously had been underestimated because these habitats are used far more at night than during the day. Regionally, soil-based agricultural crops ranked above other terrestrial habitats, and pasture was the only terrestrial habitat that was ranked highly and preferred at both scales. Pasture vegetation tends to be short, and pasture fields in the Fraser River delta are fertilized heavily and naturally with cattle manure. We recommend that managers promote the maintenance of a mosaic of soil-based agricultural crops-with a particular emphasis on naturally fertilized pastures-for dunlin and other shorebirds wintering in the Fraser delta. Terrestrial habitat fragmentation also should be kept to a minimum, as dunlin preferred large fields, likely in response to predation risk.
Skagen, S. K., Sharpe P. B., Waltermire, R. G. & M. B. Dillon (1999): Biogeographical profiles of shorebird migration in midcontinental North America. USGS Publication 555. Internet version of this publication
SkOF. Fåglar i Skåne. Anser, Suppl. (1975-1993): (Annual
Report from Scania).
Smit, C. J. & W. Wolff (eds.) (1981): Birds of the Wadden Sea. Report 6 of the Wadden Sea Working Group. Balkema, Rotterdam.
Smit, C. J. & T. Piersma (1989): Numbers, mid-winter distribution and migration of wader populations using the East Atlantic Flyway. IWRB Special Publ. 9: 24 - 63.
CP:The maximum number of Dunlin recorded on the East Atlantic Flyway, 2.2 million, was stated in this publication.
Smith, K. W., Reed, M. J. & B. E. Trevis (1999): Nocturnal and
diurnal activity patterns and roosting sites of Green Sandpipers Tringa ochropus wintering in southern England. Ring. & Migr. 19: 315 - 322.
A radio telemetric study of Green Sandpipers at their wintering site, a disused watercress bed in southern England, shows that they alternate between the watercress bed and a nearby gravel pit complex over the course of the autumn and winter. Birds spent most days feeding at the watercress bed and roosted overnight in the gravel pit complex. During extremely cold weather in January and February the birds switched to roosting at the watercress beds. Automatic activity monitoring showed that the birds were active for around 80 % of each day at all times of year. Their time active at night varied from around 16 % in autumn to over 40 % in cold conditions in midwinter. The hours the birds were active during the day and night in mid-winter were inversely proportional to the maximum daily temperature. The evidence suggests that a low level of night time activity is normal in Green Sandpipers but the high levels found during extremely cold winter conditions are the result of birds attempting to increase their daily food intake thus supporting the 'supplementary' hypothesis for nocturnal foraging.
SOF. Sveriges fåglar. (1990): 2:a uppl. Stockholm. (Swedish check-list).
Soikkeli, M. (1966): On the variation in bill- and wing-length of the Dunlin (Calidris alpina) in Europe. Bird Study 13: 256-269.
The present study deals with variation in bill- and wing-length of Dunlin in a population breeding in western Finland, and also with that appearing in the fairly large material obtained during migration at the Ottenby Bird Station, Sweden. A new method is described for distinguishing between males and females by plumage.
The population breeding in western Finland belongs to the race schinzii,in which the mean bill-lengths are 27.8 mm in males and 31.7 mm in females, and the mean wing-lengths 108.5 and 112.6 mm, respectively.
The material measured during migration at Ottenby consists mostly of Dunlin of the nominate race, in which the mean bill-lengths are 31.4 mm in males and 35.2 mm in females.
It is considered very improbable that there should be any intergradation between alpina and schinzii in northern Sweden, as claimed by Swedish workers. The Dunlin of the nominate race breeding in northern Scandinavia may however have shorter bill- and wing-lengths than other populations of alpina.(...)
CP: I spent some time studying Fig. 5 of this paper: "correlation of bill-length with wing-length in the Dunlin population breeding in western Finland". According to the paper there are 96 male and 71 female bill-lengths, 56 male and 49 female wing-lengths. Plotted in the figure are c96 male and c65 female bill-lengths - but how were these correlated with wing-lengths if there were fewer measurements of this kind? There is something fishy about the skewness of the male component distribution.
Stanley, P. I. & C. D. T. Minton (1972): The unprecedented westward migration of Curlew Sandpipers in autumn 1969. Brit. Birds 85: 365 - 380.
The unprecedented influx of juvenile Curlew Sandpipers Calidris ferruginea in Britain and Ireland during late August and early September 1969 is analysed with counts from over 250 localities, these amounting to more than 19,000 bird-days. The principal arrivals took place on 23rd and 26th August, and at the peak on 31st at least 3,500 were present, over 72 % of the records coming from the east coast of Britain.(...)An analysis of all available ringing data indicates a regular autumn migration route through the Baltic and down the Continental seaboard to Africa, some taking a more direct line back across the central Mediterranean in spring. The exceptional influx in 1969 appears to have been due to a migration unusually far to the west, this being caused by abnormally persistent cyclonic weather systems centred over the Baltic and north Russia coinciding with the departure of juvenile Curlew Sandpipers from their breeding grounds. There is some evidence, too, that in 1969 the species had had a successful breeding season.
Weight data indicate that the resting migrants were increasing their weight at up to 7 % per day and calculations suggest that most of them accumulated sufficient fat reserves in seven to ten days to fly direct to north Africa; these estimates are compatible with the rapid decline in total numbers during September. (...)
Sterbetz, I. (1992): Foods of Dunlin (Calidris alpina) in Hungary. Aquila 99: 49 - 57.
Stiefel, A. & H. Scheufler (1989): Der Alpenstrandläufer. Neue Brehm-Bücherei, nr 592. Wittenberg Lutherstadt: A. Ziemsen Verlag. A few excerpts from the text quoted here.
Stienen, E. W. M. & A. Brenninkmeijer (1997): Food and growth of Short-eared Owl, Asio flammeus.. Limosa 70: 5 - 10.
The study was performed on Griend, an islet in the Dutch Wadden Sea. (...)Pellets and plucking remains found in the immediate vicinity of the chicks revealed that Dunlins and Wood Mice made up 69 and 28 %, respectively, of prey items in 1995. (...)In 1996, however, Wood Mice made up 76 % of prey items, while Dunlin accounted for only 8 %.
Timing of the start of the breeding season seems important for the Short-eared Owl on Griend. It is suggested that the island's Wood Mice population alone does not allow for optimal growth and survival of owl chicks. When owls started breeding relatively early (1995; late March), Dunlins, present in large flocks, constituted an additional prey during the chick rearing period. This resulted in fast chick growth and good breeding success. In 1992 and 1996, Dunlins disappeared to migrate to their breeding areas one week after owl eggs had hatched; consequently, chick survival was low. (...)
Stratford, J. (1999): Ornithological fauna of Baltoji Vok&eauml;, an important bird area. Acta Zool. Lith. 9: 24 - 79. Internet version.
Incorporating two years of casual observations (1996-97) and, moreover, an in-depth year long study (1998), a complete ornithological survey of Baltoji Vokë fish pools and the adjacent Lake Papis has been completed. The results show the area to be one of the richest ornithological sites in eastern Lithuania, with over 200 bird species recorded (196 in 1998), including 90 species breeding or probably breeding and, in addition, numerous more occurring in important numbers during the migratory periods.
Stresemann, E. & V. (1966): Die Mauser der Vögel. J. f. Orn. 107, Sonderheft.
CP:Stresemann's recording "style" in translation, the bird must be a pacifica since it is moulting on breeding-grounds:
28. Aug. 1880, male, Alaska: St Michael - (followed by registration number of museum specimen). P 1 to 8 new, 9 g 3/4, 10 g 1/2 -- Almost fresh winter plumage, only a few black feathers left on belly.
Summers, R. W., R. L. Swann & M. Nicoll (1983): The effects of methods on estimates of primary moult duration in the Redshank Tringa totanus. Bird Study 30: 149 - 156.
The duration of primary moult of Redshank was estimated from various methods involving drawing straight and curved lines through a scattergram of points. Estimates ranged from 72 to 109 days. The growth of the primaries was not constant, so linear regression analysis did not fit the best line to the data, even when the curving effect of describing moult in terms of moult scores was corrected for. Linear regression analyses also gave unrealistically early values for the start and completion of moult. More satisfactory methods involved drawing a curved line through the mean dates for each moult score, or each 5 % of feather mass grown. An even spread of records (nonmoulting plus moulting birds) through the moulting season is essential to give a good estimate of duration.
Swann, R. L. & B. Etheridge (1996): Movements of waders to and from the Moray Firth. Ring. & Migr. 17: 111 - 121.
Székely, T., Freckleton, R. P. & J. D. Reynolds (2004): Sexual selection explains Rensch's rule of size dimorphism in shorebirds. Proc. Nat. Acad. USA. 101: 12224 - 12227. pdf version on the Web.
Sexual size dimorphism shows a remarkably widespread relationship to body size in the animal kingdom: within lineages, it decreases with size when females are the larger sex, but it increases with size when males are the larger sex. Here we demonstrate that this pattern, termed Rensch's rule, exists in shorebirds and allies (Charadriides), and it is determined by two components of sexual selection: the intensity of sexual selection acting on males and the agility of the males' display. These effects are interactive so that the effect of sexual selection on size dimorphism depends on male agility. As a control, we also examine dimorphism in bill length, which is a functionally selected trait. As such, dimorphism in bill length neither exhibits Rensch's rule nor is associated with sexual selection and display. Our results show that variation among taxa in the direction and magnitude of sexual size dimorphism, as manifested as Rensch's rule, can be explained by the interaction between the form and strength of sexual selection acting on each sex in relation to body size.
Thompson, P. B. A. & M. P. L. Thompson (1985): Early warning and mixed species association; the "Plover's page" revisited. Ibis 127: 559 - 562.
Thorup, O. (1999): Breeding dispersal and site fidelity in Dunlin Calidris alpina at Tipperne, Denmark. DOFT 93: 255 - 265.
Tiedemann, R. (1999): Seasonal changes in the breeding origin of migrating Dunlins (Calidris alpina) as revealed by mitochondrial DNA sequencing. J. Orn. 140: 319 - 323.
Tjørve, E. & K. M. C. Tjørve. (2007): Movements of Dunlins Calidris alpina ringed along the Norwegian coast. WSGB 112: 37 - 44.
Todd, W. E. C. (1953): A taxonomic study of the American Dunlin (Erolia alpina). J. Wash. Acad. Sci., 43: 85 - 88.
Tomkovich, P. & L. Serra (1994): (transl.) Site fidelity and the spatial structure of the populations in the Rock Sandpiper Calidris ptilocnemis and Dunlin Calidris alpina on Chukotsky Peninsula. Russ. J. Orn. 3: 13 - 30.
Tomkovich, P.S. (1998): Breeding schedule and primary moult in Dunlins Calidris alpina in the Far East. Wader Study Group Bulletin 85: 29-34.
Tomkovich, P. & L. Serra (1999): Morphometrics and Prediction of Breeding Origin in some Holarctic Waders. Ardea 87: 289 - 300.
Tomkovich P.S., E. G. Lappo & E. E. Syroechkovski Jr (2000): Ringing and migratory links of Taimyr waders. Heritage of the Russian Arctic. Research, Conservation and International Co-Operation. Proc. of the Int. Sc. Willem Barents Memorial Arctic Conservation Symposium held in Moscow, 10-14.3.93: 458 - 474.
Ringing of waders in the Taimyr Autonomous Okrug (district), Northern Siberia, dates back to the 1960's. In 1989-1996, a total of 5,700 waders of 24 species were ringed and some were additionally colour-marked as one of the activities of the International Arctic Expedition organised by the Institute of Ecology and Evolution, Russian Academy of Sciences. Forty-six recoveries of 11 species have so far been obtained including 15 birds marked on the Taimyr Peninsula and 31 ones ringed elsewhere. The highest recovery rate was that in marked Red Knots (Calidris canutus). Indeed, 2.6 % of the 312 birds ringed at the breeding grounds were recovered during the study. Marking Little Stints (Calidris minuta) turned out to be least efficient, no recovery having been obtained despite the most extensive ringing of these birds (over 1,700 individuals). Curlew Sandpipers (Calidris ferruginea) breeding on the Taimyr Peninsula were shown to have the broadest winter distribution range which encompasses western and south-eastern Europe, South Africa, the Indian subcontinent and Australia. It is concluded that the geographic position of Taimyr in the centre of northern Siberia, its wide and diverse expanses of open marshy habitats, and geological history of the peninsula are collectively responsible for its paramount importance for the reproduction of many wader species using different migratory routes.
Tsipoura, N. & J. Burger (1999): Shorebirds and surf clams: An unusual interaction. Waterbirds 22: 140 - 141.
Tubbs, C. R., Tubbs, J. M. & J. S. Kirby (1992): Dunlin Calidris alpina alpina in The Solent, southern England. Biol. Cons. 60: 15 - 24.
Underhill, L. G. & A. Joubert (1995) Relative masses of primary feathers feathers. Ring. & Migr. 16: 109 - 116.
A knowledge of the relative masses of the primary feathers is necessary to compute the percentage of feather mass grown by a bird moulting its primaries, as a step towards estimating the parameters of moult using the Underhill-Zucchini moult model. Also, wing shape characteristics can be described by fitting a polynomial regression model to the relative feather masses. This paper presents relative feather mass data for 38 species, primarily southern African. Further data are required to evaluate the concept of fitting mathematical models to describe wing shape.
Van Rommen, M., van Turnhout, C., van Winden, E., Koks, B., Goedhart, P., Leopold, M. & C. Smit (20055) Trends van benthivore watervogels in de Nederlandse Waddenzee 1975-2002: grote verschillen tussen schelpdiereneters en wormeneters. Limosa 78: 21 - 38. pdf download.
In this paper trends in the numerical presence of 18 benthivorous waterbird species in the Dutch Wadden Sea (Figure 1) in the period 1975-2002 are analysed, using all available counts and U-Index to impute missing counts. Three species have decreased in
numbers, ten species have increased, and five species have fluctuated around a stable
mean. However, for ten species the trend in the period 1975/76-1990/91 differed significantly from that during 1991/92-2001/02. This concerns especially species that mainly feed on either worms or shellfish. Furthermore, worm-eating species and shellfish-eating species show opposite trends, a difference that is significant for the period 1991/92-2001/02. All four species which depend on bivalves have decreased (Common Eider, Eurasian Oystercatcher, Red Knot and European Herring Gull), whereas five out of six worm-eating species have increased. The larger the contribution of shellfish in the diet, the larger the population decrease in 1991/92-2001/02. Other studies have shown that the recent decrease in Common Eider and Eurasian Oystercatcher
numbers are at least partly caused by deteriorating feeding opportunities. Intertidal mussel
beds have largely disappeared in the early nineties (due to overfishing, poor spatfall and
possibly winter storms) and cockles were heavily exploited by commercial mechanised
fisheries. For Red Knot especially the disturbance of the sediment by mechanised cockle
fisheries is important with a range of effects on th quality and quantity of their food. The recent, broad increase of numbers of worm-eating species may be linked to a shift in the ecosystem
(reduced shellfish stocks, increased worm stocks) but the mechanisms underlying this
change remain to be identified fully.
Warnock, N., Page, G. W. & L. E. Stenzel (1995) Non-migratory movements of Dunlins on their California wintering grounds. Wilson Bull. 107: 131 - 139. Internet version of this paper..
.-In 1991-1992, we tracked 150 marked Dunlins (C&i&s alpina) from two central California coastal sites to ascertain if they made winter-time movements to inland areas and examined census data from these and other coastal sites to document the possible extent and frequency of these movements. Between December 1991 and January 1992, Dunlin numbers at four central California coastal sites decreased by 44-84% during periods
of heavy rain. Subsequently, six or seven of the marked Dunlins from one of these sites were located inland, up to 140 km away. The sudden disappearance of more than 40% of the wintering Dunlins from this coastal area in 10 of 21 years suggests that such movements may be fairly frequent. Median (October-March) numbers of Dunlins at this site during the 21 years were negatively correlated with local rainfall, suggesting a relationship between winter storm activity and the level of use of coastal sites. It remains to be determined whether deteriorating conditions in coastal wetlands or the increased availability of inland habitats related to winter storms is responsible for reducing Dunlin winter-time use of coastal sites. Received 28 March 1994, accepted 6 Sept. 1994.
Warnock, N., Page, G. W. & B. K. Sandercock (1997) Local survival of Dunlin wintering in California. The Condor 99: 906 - 915. Internet version of this paper.
We estimated local annual survival of 1,051 individually color-banded Dunlin (Calidris alpina) at Bolinas Lagoon, California from 1979 to 1992. Resighting rates for birds banded as adults varied significantly among years, and resighting rates for first-year birds varied by sex and year. No significant differences in local survival rates were found
between males and females in any age classes. First-year birds had lower local survival rates than adults. We suspect that raptor predation accounted for much of this difference and other variation in survival rates. Adult Dunlin had lower local survival rates in the year of capture than in subsequent years. Variation in resighting of some groups of individuals
including transient Dunlin may account for some differences. However, capture and release of Dunlin may induce short-term behavioral changes that increase the risk of depredation by avian predators within the first few days after capture.
Warnock, N., Takekawa, J. Y. & M. A. Bishop (2004) Migration and stopover strategies of individual Dunlin along the Pacific coast of North America. Can. J. Zool. 82: 1687 - 1697. Internet link to this paper
We radio-marked 18 Dunlin, Calidris alpina (L., 1758), at San Francisco Bay, California, and 11 Dunlin at Grays Harbor, Washington, and relocated 90% of them along the 4200 km long coastline from north of San Francisco Bay to the Yukon–Kuskokwim Delta, Alaska. The Copper River Delta, Alaska, was the single most important stopover site, with 79% of the marked birds detected there. Our second most important site was the Willapa Bay and Grays Harbor complex of wetlands in Washington. The mean length of stay past banding sites ranged from 1.0 to 3.8 days. Controlling for date of departure, birds banded at San Francisco Bay had higher rates of travel to the Copper River Delta than those banded at Grays Harbor. The later a bird left a capture site, the faster it traveled to the Copper River Delta. Length of stay at the Copper River Delta was inversely related to arrival date. We did not find any effect of sex on travel rate or length of stay. Combining the results of this study with our previous work on Western Sandpipers, Calidris mauri (Cabanis, 1875), reveals variation of migration strategies used within and among shorebird species along the eastern Pacific Flyway.
Watson, G. (1977): The mechanism of feather replacement during natural molt. The Auk 80: 486 - 495.
1. Observations of feather replacement in live and preserved specimens of several species of birds during natural molt demonstrate that old feathers are actively pushed out of the follicles attached to the tips of the sheaths of the incoming feathers. 2. There may be a constriction at the zone of juncture but the outer layer of the calamus of the old feather and the sheath of the new feather are apparently continuous. 3. The old feathers are broken off when the new feather sheath becomes keratinized. 4. The physical connection is still present when growth is renewed in a papilla which has been dormant 10 months. 5. This mechanism of feather replacement has been observed in eight diverse orders of birds. 6. Molt consequently appears to be a single growth process actively concerned only with the new generation of feathers. The old generation is passively shed. 7. Molt nomenclature should reflect this natural relationship between the growth process and the generation of feathers it produces.
Wenink, P. W. (1994) Mitochondrial DNA sequence evolution in shorebird populations. Dissertation. Wageningen 1994. Wageningen Dissertation Abstracts.
A few excerpts from the summary (references excluded):"(...)There are several reasons why mtDNA is the molecule of choice to probe the recent evolutionary history of a species. Most importantly, mtDNA accumulates substitutions at a high average rate that permits the tracing of genealogies within the time frame of speciation. The population structure of shorebirds, like that of arctic-breeding waterfowl, must have been influenced dramatically by the Pleistocene glaciations (mainly during the last one million years). The fastest evolving part of the mtDNA genome, the non-coding control region, offers sufficient genetic resolution to reveal differentiation of such recent origin. The typical mode of maternal inheritance, the absence of recombination, end the presumed neutrality of substitutions, are characteristics that add to the suitability of mtDNA for the construction of robust phylogenies.
(...)The dunlin, on the other hand, became divided into several isolated populations during the Pleistocene and has retained a significant amount of intraspecific genetic diversity until the present.
(...)A genealogical tre relating (35 different genotypes) revealed five major clusters. Each cluster has high geographic specificity. The cluster containing the most divergent sequences is present along the Atlantic coast of North America and represents the dunlin population breeding in arctic central Canada. Two clusters of genotypes are located principally in western Europe and central Siberia. Evidence for a low level of gene flow between these latter two populations was provided by three individuals whose genotypes suggested they were immigrants. Two other clusters are found along the Pacific coast of North America.(...)
A plausible scenario for the genetic divergence of the major dunlin lineages is the ancestral fragmentation of populations over tundra refugia, that were created by the extensive glaciations of the northern hemisphere during the Pleistocene. Prolonged isolation of populations of reduced size increased the effect of genetical drift and this may have led to the observed mtDNA monophyly. The different lineages continuously diverged by the process of mutation. This ancient subdivision has been retained after retreat of the icesheets, most likely as a result of the strong site-fidelity of dunlins to their breeding ground. [CP: Fidelity to wintering grounds and maybe equally to resting and staging grounds not included here!] Dunlin populations could thus not become homogenized genetically because gene flow is not extensive enough between them.
(...)Phylogeographic groups can be correlated to the global geography of morphometrically defined subspecies in the dunlin. Whereas several disputed subspecies gain support from the genetic data (i.e. C. a. hudsonia in central Canada and C. a. centralis in central Siberia), other subspecies merge into the same phylogeographic group. No major phylogenetic divisions are apparent among the morphometrically dissimilar populations in north-eastern Greenland, Iceland, the Baltic Sea, and Norway (recognized until now as three to four different subspecies). Gauged by the depth of the other phylogenetic splits in dunlin, they can jointly be referred to as C. a. alpina.(...)
It is thus revealed how morphology lacks an evolutionary perspective in the determination of intraspecific taxonomy. (My emphasis; CP) For the dunlin, a parallel morphological evolution of genetically divergent populations, as well as the opposing process of morphological divergence of evolutionary closely related populations, is observed. Morphometric characters employed in intraspecific avian taxonomy are suffering from homoplasy, either as a result of character plasticity and environmental induction, or because of very high mutation rates and strong directive selection acting on phenotypes. Because morphometrically different dunlin populations are often mixed outside the short breeding season, environmental induction of morphology seems unlikely, although this possibility remains to be investigated."
CP:This boils down to two alternatives: genetically defined "haplotypes" (the individual maybe breeding in the main area of another haplotype) and morphologically more or less well-defined "population groups". In the field we can only discern the latter groups, and the aim of the field-worker must be to obtain maximum morphological differentiation, using all characters available. It seems to me, Dunlin are not very "mixed" outside the breeding season - they know their kin, always know their kin and seek it.
Wenink, P. W. & A. J. Baker (1996): Mitochondrial DNA lineages in composite flocks of migratory and wintering Dunlins (Calidris alpina). Auk 113: 744 - 756
Mitochondrial DNA (mtDNA) control-region sequences of 52 migratory and wintering Dunlins (Calidris alpina) from around the world were determined with direct sequencing of PCR products. The genetic lineages detected in these birds are identical to those found previously in a much larger sample of 155 breeding Dunlins from their northern circumpolar range. Samples of nonbreeding Dunlins from both sides of the Pacific reveal a mixture of two lineages that breed separately in eastern Siberia and Alaska. The presence of Dunlins with an eastern Siberian haplotype along the west coast of North America indicates that the Bering Strait does not represent a biogeographic barrier to Dunlin migration. Dunlins wintering in eastern Asia most likely originated from the discrete breeding population in northern Alaska because they possess haplotypes that were found predominantly in birds from this region. Similarly, Dunlins from staging and wintering sites in Europe and western Asia reveal a mixture of two mtDNA lineages that were previously found confined largely to European and central Siberian breeding grounds. Limited gene fiow between these breeding areas, however, precludes definitive allocation of individuals to their population of origin on the basis of mtDNA analysis alone. Body mass, time of migration, and molting pattern seem to be associated with the mtDNA types of migratory Dunlins in Europe, but data are too sparse to determine whether these characters are useful adjuncts in assigning nonbreeding birds to populations that correspond to the major genetic lineages. Overall, the genetic composition of nonbreeding populations indicates the confluence of breeding populations on southward migration. Because of strong phylogeographic population structure in Dunlins on their breeding grounds, mtDNA analysis can be extremely useful in defining broad migration corridors or fiyways, and in determining staging and wintering areas used by the major breeding populations.
Wenink, P. W., Baker, A. J., Rösner, H.-U. & M. G. J. Tilanus (1996): Global Mitochondrial DNA Phylogeography of Holarctic Breeding Dunlins (Calidris alpina). Evolution 50: 318 - 330.
Comparison of mitochondrial DNA (mtDNA) control-region sequences of 155 dunlins from 15 breeding populations confirmed the existence of five major phylogeographic groups in the circumpolar breeding range of this migratory shorebird species. Time estimates of the origin of groups, based on sequence divergences and a molecular clock for birds, suggest a scenario of repeated fragmentation of populations in isolated tundra refugia during the late Pleistocene. The distribution of about three-quarters of all detected molecular variance between phylogeographic groups attests to the strongly subdivided genetic population structure in dunlins that is being maintained by natal philopatry. Each mtDNA phylogeographic group can be related to a morphometrically defined subspecies, but several other recognized subspecies are not supported by monophyletic mtDNA lineages within their purported ranges. More detailed analysis of several European populations reveals low amounts of gene flow and the partitioning of a substantial fraction of molecular variance between them. This ongoing evolution of population-genetic structuring within the European phylogeographic group most likely started with the last retreat of the ice sheets some 10,000 years ago. Dunlins thus provide one of the clearest examples of the linkage between historical and contemporary components of mtDNA phylogeographic structuring in birds.
Wennerberg, L. (2001): Breeding origin and migration pattern of dunlin (Calidris alpina) revealed by mitochondrial DNA analysis. Molecular Ecology 10: 1111 - 1120.
The large-scale migration of birds has been studied extensively by recoveries of ringed birds. However, there is very little ringing data from the arctic breeding grounds of waders. Here, the migration pattern of the dunlin, Calidris alpina, is studied with population genetic markers, using haplotype frequencies to estimate the breeding origin of migrating and wintering populations. Polymerase chain reaction (PCR) and restriction analysis of DNA from the mitochondrial control region was used to study the breeding origins of morphologically similar winter populations in the western Palaearctic, and to describe the population structure of the dunlin during winter. Also migrating dunlin from various stopover sites in Europe, Africa and Asia, were analysed with respect to their mitochondrial DNA (mtDNA) haplotypes. The genetic markers clearly show that the dunlin has a parallel migration system, with populations breeding in the western Palaearctic wintering mainly in the western part of the wintering range, and dunlin populations breeding further east wintering further east. The results also show that the distance between breeding and wintering area increases eastwards in this region.
Whitfield, D. P. (2003): Density-dependent mortality of wintering Dunlins Calidris alpina through predation by Eurasian Sparrowhawks Accipiter nisus. Ibis 145: 432 - 438.
Density-dependent mortality in wintering shorebirds is critical to shorebird population dynamics, but is difficult to study and demonstrate. Most winter mortality of small shorebirds probably results from predation by raptors. Over 13 winters, I studied Eurasian Sparrowhawk Accipiter nisus predation on wintering Dunlins Calidris alpina at a rocky shore in south-east Scotland, a site apparently of marginal suitability for wintering Dunlins. Most Dunlins on the study site were juveniles (first winter birds), and winter juvenile mortality rate due to Sparrowhawk predation was strongly and positively related to Dunlin density (maximum winter count). There was no indication of any marked effect of weather on Dunlin winter mortality rate, except that mortality was slightly greater in winters with lower temperatures. Dunlin mortality was unrelated to the mortality through Sparrowhawk predation of a preferred prey, the Redshank Tringa totanus, or to sighting rates of hawks, suggesting that increased hunting of Redshanks by hawks or a numerical response by hawks were not involved in density-dependent mortality of Dunlins.
Witherby, H. F. et al. (1958) in: The Handbook of British Birds. Vol. IV. London: H. F. & G. Witherby Ltd. A short remark by H. F. Witherby quoted.
"Dr C. B. Ticehurst mentioned two large birds taken in Fair Is. on Sept. 23, 1905, which he considered to be C. a. sakhalina. I have examied these: female wing 116, bill 40, male wing 119, bill 35. The bills are certainly very large, but the wing of the female is short for sakhalina, and in both birds there is only slight edging of white on the outer webs of the inner primaries instead of the white extending to the rhachis as is usual in sakhalina.
Among other large British-taken birds, I have examined only three with a considerable amount of white on the outer webs of the inner primaries (...) In the last the white just reaches the rhachis and in the other two not quite. These may be referable to C. a. sakhalina, but before admitting that race to the list I think we should have more definite evidence, as very occasionally examples of C. a. alpina have an unusual amount of white on inner primaries."
CP: This is history, passed by recent genetical research. I just want the quotation here as a morphological reference.
Wlodarczak, A. (1999): Present status of breeding populations of Dunlin Calidris alpina schinzii in Poland. Wader Study Group Bulletin 88: 5
Wlodarczak, A. (1999): Distribution and numbers of the Polish population of the Dunlin Calidris alpina schinzii. Not. Orn. 40: 45 - 49.
Worrall, D. H. (1984): Diet of the Dunlin Calidris alpina in the Severn Estuary. Bird Study 31: 203 - 212.
Wymenga, E., Engelmoor, M., Smit, C. J. & T. M. Van Spanje (1990): Geographical breeding origin and migration of waders wintering in West Africa. Ardea 78: 83 - 112.
This paper discusses the geographical breeding origin and migration routes of 3.5 million waders using the Banc d'Arguin, Mauritania and Guinea-Bissau, based upon morphometrical data and supplementary ringing recoveries. For several species our analyses confirm earlier findings on breeding areas and migration routes. For at least part of the Ringed and Grey Plovers, Redshanks, and to a lesser extent also Bar-tailed Godwits, Whimbrels, Curlews and Turnstones, there are indications that birds wintering in Guinea-Bissau originate from breeding areas further north and east, as compared to birds wintering in Mauritania. The morphological characteristics and measurements do not allow the determination of the exact location of the breeding areas. This is due to clinal gradients in measurements, as a result of which there is much overlap in sizes. During spring migration most wader species wintering in W. African coastal wetlands travel via a route following the W. African and W. European coastline. Little Stint, Curlew Sandpiper and Curlew are exceptions to this rule. There are indications that at least part of these birds migrate through NW Africa, the Mediterranean and the Black Sea area.
Yoo, Jeong Chil. (1994): Seasonal fluctuations, biometrics, fat and non-fat masses of Dunlins (Calidris alpina sakhalina) migrating to Sammok Island on the west of Korea. Korean Journal of Ornithology 1: 15 - 24.
Yosef, R. & W. Meissner (2006): Seasonal age differences in weight and biometrics of migratory Dunlins (Calidris alpina) at Eilat, Israel. Ostrich 77: 67- 72.
This study was undertaken to understand the migratory strategies of the Dunlins (Calidris alpina) caught in Eilat, Israel, before and after they accomplish the crossing of the combined ecological barrier of the Sinai, Sahara and Sahel deserts. Between 1999–2001, a total of 410 adults and 342 juveniles were banded. The significant difference in mean wing length between birds caught in autumn and spring reflects the degree of abrasion of the outer primaries during over-wintering in Africa. Dunlins caught in Eilat in autumn and early winter had a mean wing length 1.4–1.9mm longer than in the spring. The rate of body mass increase was comparatively high and the mean body mass of the heaviest 10% of Dunlin at Eilat was 56.2g (SE ± 0.6, N = 80). The heaviest birds from Eilat carried on average about 10g of fat with a lipid index (fat mass as a percentage of total body mass) of 18%. These reserves allow a flight of approximately 1 000km, which is probably sufficient for continued migration to more southerly wintering grounds.
Zajac, R. (1980): Different autumn migration rates of sexes in the Dunlin Calidris a. alpina, as determined by means of normal probability paper. Acta orn.
17: 107 - 118.
Zwarts, L., B. J. Ens, M. Kersten & T. Piersma (1990): Moult, mass and flight range of waders ready to take off for long-distance migrations. Ardea 78: 339 - 364.
Wader species wintering on the Banc d'Arguin increased their body mass by about 40 % during the 4 - 6 weeks before their departure in spring. This estimate is based on 1) the empirical fact that most waders which had finished or suspended their body moult into summer plumage were heavy and thus ready to take off, and 2) the assumption that only the heaviest birds in the population left, which allowed the mass of disappearing waders to be estimated from counts and the frequency distribution of body masses in samples of captured birds. The mass gain on the Banc d'Arguin is just over 1 % per day, when expressed as a proportion of winter mass. A review of studies on waders preparing for migration shows that 1) the total migratory reserve adds 20-80 % to winter mass, 2) the rate of mass gain is 0.1-4
% per day and 3) the period of mass increase lasts four weeks on average, but longer if waders prepare for spring migration on the wintering areas. We suggest that all wader species leaving the Banc d'Arguin at the end of April and the beginning of May are able to reach SE and NW Europe without refuelling. This seems only possible if current equations to predict flight range systematically underestimate this range, even when the energetic benefits of favourable winds at high altitude are taken into account.
Zwarts, L. & J. H. Wanink (1993): How the food supply harvestable by waders in the Wadden Sea depends on the variation in energy density, body weight, biomass, burying depth and behaviour of tidal-flat invertebrates. Neth. J. Sea Res. 31: 441 - 476.
For several reasons, waders in the Wadden Sea face a large seasonal and annual variation in their food supply. Observations on a tidal flat in the Dutch Wadden Sea have shown that:
1. - (1) The average energy density of ten invertebrate prey species varies between 21 and 23 kJ·g-1 AFDW. In Scrobicularia plana and Mya arenaria, but not in Macoma balthica, the energy density is 10% lower in winter than in summer.
2. - (2) Depending on the species, body weights of prey of similar size are 30 to 60% lower in winter than in summer.
3. - (3) The year-to-year fluctuation in standing-crop biomass is larger in some species than in others, the difference depending mainly on the frequency of successful recruitment. The overall biomass of the macrobenthos in winter is half of that in summer, but the timing of the peak biomass differs per species.
4. - (4) The burying depth varies per species: Cerastoderma edule live just beneath the surface, while M. balthica, S. plana, M. arenaria, Arenicola marina and Nereis diversicolor bury more deeply and the majority of these prey live out of reach of the bird's bill. In all six species, burying depth increases with size. There is no seasonal variation in depth of C. edule and M. arenaria, but the four other species live at most shallow depth in early summer and most deeply in midwinter. Burying depths in winter vary from year to year, but are unrelated to temperature. Neither has temperature any effect on depth within months. For knot Calidris canutus feeding on M. balthica, the fluctuation in the accessible fraction was the main source of variation in the biomass of prey that is actually harvestable, i.e. the biomass of prey of suitable size that is accessible. Accordingly, the paper reviews the available data on the temporal variations in accessibility, detectability, ingestibility, digestibility and profitability of prey for waders. Only a small part of the prey is harvestable since many accessible prey are ignored because of their low profitability, while many profitable prey are inaccessible. The profitability of prey depends on their size and weight but also on their depth in the mud, since handling time increases with burying depth. A simple biomechanical rule explains why the handling time of small prey increases with bill length and why large, long-billed waders ignore a disproportionately larger part of the small prey. The fraction detectable for visually feeding waders is usually very low, especially when the temperature of the substrate is below 3-6°C. Waders vary their prey choice over the year in response to the changes in the availability and profitability of their different prey species. The food supply harvestable by waders is much lower in winter than in summer. For waders wintering in the Wadden Sea, the food supply may be characterized as unpredictable and usually meagre. Waders wintering in NW Europe are concentrated in coastal sites where the average surface temperature is above 3°C. This probably cannot be explained by a greater burying depth, and only partly by a lower body condition, of prey in colder areas. Yet the harvestable fraction is lower in colder sites, especially for sight-feeding waders, as invertebrates are less active at low temperatures. However, the lower energetic cost of living and reduced chances of the prey being covered by ice may also contribute to the waders' preference for warmer sites.
To "Studies of migrating Dunlin Calidris alpina in the Sound area, S. Sweden: Introduction"
To "Phenology and biometry of Dunlin Calidris alpina migrating by way of the Sound area, S. Sweden"
To "Migrating Dunlin Calidris alpina in the Baltic area: the moult issue"
To "Risk-prone or risk-averse? Dunlin Calidris alpina migrating with and without moult-gaps in the Baltic area"
To "Wintering and spring staging Dunlin Calidris alpina in the south Baltic area"
To "Migratory progress of juvenile and adult Dunlin Calidris alpina from two perspectives: the Baltic and the Waddensea"
To "Bill-length distributions in Dunlin Calidris alpina"
To the bill length account
About "adult buff" coverts
To the Meissner scale
To the Dunlin literature list A - J
To wader literature list A - L
To the Dunlin literature list M - Z
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