Energetics and flight performance:

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. The comment is personal, it points out errors and possible follow-ups, it is begun: CP:
The whole "genre" has a tendency to reproduce a few basic papers and the original Odum paradigm again and again, still there is some slow progress; what was regarded as true and correct in 1963 is not entirely to the point in 2003. Quotation of old papers leads to contradictions in new ones; I cannot see through all these ambiguities, but I will do my best.

A, B, C, D, E, F, G, H, I, J, K

Akriotis, T. (1991): Weight changes in the Wood Sandpiper Tringa glareola in south-eastern Greece during the spring migration. Ring. & Migr. 12: 61 - 66.

The weight changes og 167 Wood Sandpipers at a staging post in south-eastern Greece are analysed. Weight was significantly affected by body size, time of day, date and age but no difference could be found between years which differed in habitat conditions as well as the area of suitable habitat available. The rate of weight gain of individual birds was much higher than that of the population as a whole,presumably due to the continual flux of migrants. Fat levels also increased significantly with date, in accordance with the increase in weight. The results show a remarkable resilience of Wood Sandpipers to changed habitat conditions under extreme climatic events and contrast with the great variability in mean weights observed at different sites of their migration route.

Arcas, J. (2001): Body weight variation and fat deposition in Common Sandpipers Actitis hypoleucos L. during their autumn migration in the Ría de Vigo, Galicia, north-west Spain. Ring. & Migr. 20: 216-220.

Body weight variation and fat deposition of 111 Common Sandpipers are analysed in the Ria de Vigo, North-west Spain, during their autumn migration. Retrapped birds did not show notable fat deposition and no body weight variation was found, but long staging periods were recorded. Discussions about body condition and its implications on the migratory strategy of the species are presented.

Ash,J. S. (1969): Spring weights of trans-saharan migrants in Morocco. Ibis 111: 1 - 10.


Baccetti, N., A. de Faveri & L. Serra. (1992): Spring migration and body condition of Common Sandpipers Actitis hypoleucos on a small Mediterranean Island. Ring. & Migr. 13: 90 - 94.

42 Common Sandpipers were examined at a stopover site on a small island in the central Mediterranean during the spring migration. Some details about the timing of passage and body conditions are given. Birds had very low mean body mass, indicating that they were probably at the end of one of the most arduous parts of their journey, although none of them appeared exhausted. The absence of information about body mass at more southerly latitudes precludes assessment of the role of insular stopover sites in relation to the species' overall migration strategy. A hopping strategy, at least during spring Mediterranean crossing, seems possible.

Baggott, G. K. (1986): The fat contents and flight ranges of four warbler species on migration in North Wales. Ring. & Migr. 7: 25-36.

The fat contents of four warbler species killed during a migratory flight in N. Wales are reported for both spring and autumn. From the fat content and the wingspan the potential still-air flight range and flight times are calculated for individual birds by the formulae of Pennycuick (1975): the inaccuracies of these predictions are discussed in relation to attainable range. For three of the warbler species examined (Willow Warbler, Sedge Warbler and Whitethroat) the ranges predicted are consistent with the known migratory destinations of these species in autumn. The ranges predicted for the fourth species, the Grasshopper Warbler, indicate that in autumn some birds are capable of reaching S. France in a single migratory flight. In spring, potential flight ranges of the Willow Warbler, Grasshopper Warbler and Whitethroat suggest that these birds could reach destinations only within the British Isles. However, some Sedge Warblers had sufficient fat to reach Norway in a single flight in still air. In both spring and autumn the times required to fly the predicted still-air ranges are mostly less than 24 hours. The Willow Warbler, Sedge Warbler and Whitethroat are species that scale in an isometric manner; the Grasshopper Warbler is not similarly proportioned as it has a short wingspan for its body weight. A method based on isometric scaling is developed for the prediction of relative flight ranges. All species had markedly larger wingspans in the spring compared with the autumn.

Baillie, S. M. & I. L. Jones. (2003): Atlantic Puffin (Fratercula arctica) chick diet and reproductive performance at colonies with high and low capelin (Mallotus villosus) abundance. Can. J. Zool. 81: 1598 - 1607.

We compared nestling diet and growth, breeding, phenology, breeding success, and adult mass of Atlantic Puffins (Fratercula arctica) between two seabird colonies adjacent to ocean habitat with presumed high and low capelin (Mallotus villosus) abundance in 1996 - 1998. We hypothesized that puffins at their colony at Gannet Islands, Labrador, where capelin were scarce, would exhibit lower reproductive performance than at Gull Island, Witless Bay, where capelin were abundant. Historically, capelin comprised approximately 60 % - 95 % of the chick diet biomass at both colonies. In the late 1990s, puffin chicks at the Gannet Islands received 3 % - 24 % capelin (by mass), which was 39 % - 97 % less than was received at Gull Island. Postlarval sandlance (Ammodytes sp.) comprised up to 49 % (by mass) of the chick diet at the Gannet Islands. Hatching success and fledge success estimates at the Gannet Islandsin 1997 - 1998 were statistically similar to those at Gull Island in 1998. Fledge mass (expressed as percentage of adult mass) was similar between Gannet Islands (69 %) and Gull Island (68 %). The high interyear variability in chick diet at both colonies and the low variation in breeding performance during our study suggest that Atlantic Puffins in Labrador are resilient to large-scale prey-base changes. Internetversion av denna uppsats

Bairlein, F. (1987): The migratory strategy of the Garden Warbler: a survey of field and laboratory data. Ring. & Migr. 8: 59 - 72.

Garden Warblers appear to be equipped with a migratory strategy which matches the problems arising from migration very well. They have innate endogenous programmes which determine the seasonal events for migration. They exhibit strong habitat preferences in resting areas which are likely to be endogenously controlled and which allow the specimens to be well accomodated in the various stopover areas. They possess physiological and behavioural adaptations in their nutrition which guarantee optimal fattening prior to migratory flights. Garden Warblers apparently avoid the risk of dehydration during long nonstop flights across the Sahara by crossing the desert in stages with regular stopovers at suitable sites rather than in one long hop.

Bairlein, F. (1988): Herbstlicher Durchzug, Körpergewichte und Fettdeposition von Zugvögeln in einem Ratsgebiet in Nordalgerien. Vogelwarte 34: 237 - 248.

Banks, K. W., H. Clark, I. R. K. Mackay, S. G. Mackay & R. M. Sellers (1989): Biometrics and pre-migratory fattening in the Snow Bunting Plectrophenax nivalis. Ring. & Migr. 10: 141 - 157.

Barrett, R. T., R. Fieler, T. Anker-Nilssen & F. Rikardsen (1985): Measurements and weight changes of Norwegian adult Puffins Fratercula arctica and Kittiwakes Rissa tridactyla during the breeding season. Ring. & Migr. 6: 102 - 112.

There is a steady increase with latitude in the size of puffins and Kittiwakes breeding in Norway. Data which support earlier suggestions to disregard the subdivision of F. a. arctica and F. a. grabae are presented. Males of both species were consistently heavier and larger than females in measurements of wing length, head length, bill length and bill depth. Discriminant analyses showed that head length, sometimes combined with bill depth, distinguished the sexes most precisely. Both sexes of both species steadily lost weight from the start of the incubation to the peak chick feding period. It is argued that this weight loss is voluntary and adaptive.

Basciutti, P., O. Negra & F. Spina (1999): Autumn migration strategies of the Sedge Warbler Acrocephalus schoenobaenus in northern Italy. Ring. & Migr. 18: 59 - 67.

Autumn migration strategies of the Sedge Warbler have been investigated through standardized mist-netting in two reed-beds in Northern Italy (Val Campotto and Palude di Cona) between 1988 and 1990. Data gathered from a total sample of 2,113 birds indicate a clear Scandinavian origin of staging migrants and a consistently earlier passage of adults. Adult birds are larger and seem to be at more advanced stages of fat accumulation than juveniles, which show body mass values well below those proposed for birds ready to take off for long flights. Most birds are trapped during the first hours after dawn; the extremely low local retrapping rate in both sites suggest that freshly landed migrants may soon leave these reed-beds, which seem to be particularly poor in food. The fattening strategy adopted by Sedge Warblers migrating through the Central European flyways surely deserves further investigation in order to clarify how the birds gain adequate reserves to cross the Mediterranean and the Sahara.

Bensch, S. & B. Nielsen (1999): Autumn migration speed of juvenile Reed and Sedge Warblers in relation to date and fat loads. The Condor 101: 153 - 156.

We analyzed speed of migration in two congeneric warblers, the Reed and Sedge Warbler, Acrocephalus scirpaceus and A. schoenobaenus. Sedge Warblers migrated at a higher speed than Reed Warblers. The two species showed similar rates of fat deposition at our Swedish study site, although Sedge Warblers departed with lower fat loads. The higher speed of migration in Sedge Warblers and their lower departure fat loads suggest that they encounter stopover sites which offer higher relative fat deposition rates farther south. The amount of visible fat at the time of banding was positively related to the speed of migration. Estimates of speed of migration for the two species suggest that the recoveries were situated on average 76 - 111 km farther south per (unit) increase in fat score, corresponding to 58 - 85 % of the expected distance a bird can cover by using the fuel of one unit of fat score.

Bibby, C. & R. E. Green (1981): Autumn migration strategies of Reed and Sedge Warblers. Orn. Scand. 12: 1-12.

This paper compares the patterns of migration of two congeneric warblers, moving from Britain to Africa, and aims to see how these might be influenced by the distribution of food supplies. Most Sedge Warblers fattened in southern England or northern France and overflew Iberia, while Reed Warblers paused and fattened in Portugal. The occurrence, duration of stay and rate of weight gain of Sedge Warblers depended on the abundance of the plum-reed aphid whose seasonality and distribution was broadly sufficient to predict the migration pattern. Reed Warblers showed no similar restriction of diet, did not respond to aphid abundance and were able to achievea similar rate of weight gain any time in September or October in Portugal. Migration strategies are discussed in evolutionary terms and shown to be appropriate responses to the pattern of food availability for birds with different feeding adaptations.

Birt-Friesen, V. L., Montevecchi, A., Cairns, D. K. & S. A. Macko (1989): Activity-specific Metabolic Rates of Free-living Northern Gannets and other Seabirds. Ecology 70: 357 - 367.

Field and activity-specific metabolic rates of 20 free-living Northern Gannets (Sula bassana; mean mass = 3.21 kg) rearing chicks at Funk Island, Newfoundland, were measured using doubly labeled water and activity timers. Field metabolism (FMR) averaged 4865 kJ/d or 6.6 x basal metabolism (BMR). Regression analyses indicated a metabolic rate of 144 kJ/h while at the nest or on water, 349 kJ/h during flight, and 250 kJ/h during diurnal time at sea. These metabolic rates are high, probably because of costs of thermoregulation and flapping flight. BMR was slightly lower than predicted. Statistical analyses of metabolic rates of free-living seabirds indicated that rates are elevated in seabirds in cold-water regions and in seabirds that use flapping flight, but do not vary with phylogenetic order. FMR was correlated strongly with both BMR and metabolism at the nest. Population energy models may gain accuracy if metabolic rates are either expressed as multiples of metabolism at the nest or calculated from allometric equations appropriate for the species' activity pattern, oceanographic regime, and foraging mode.

Blyumental, T. I. (1973): Development of the fall migratory state in some wild passerine birds (bioenergetic aspect). In: Bykhovskii, B. E. ed. Bird migrations. Ecological and physiological factors: 125-218.

Boddy, M. (1984): Body weights of adult and juvenile Lesser Redpolls in central and southern England. Ring. & Migr. 5: 91 - 100.

Almost 10000 body weights of adult and first-year Leser Redpolls were obtained from a variety of sites in southern and central England, including an intensive study in Nottinghamshire during 1977 - 80. The mean weights of adult males were low (11.2 - 11.4 g) during May to July; this was the only time of year that adult females were heavier. During late May, 40 % of females weighed more than 12.5 g, and the corresponding values in July was 30 %. These birds showed evidence of being involved in egg-laying. Males which had commenced moult showed an initial increase of 0.2 g in mean boddy weight, whilst mean weight of females had declined by 0.75 g at the same stage. Subsequent weight increase during moult was also less for females, and they completed moult at a mean of 11.3 g, compared with 12 g for the males. Juveniles continued weight recession after fledging, with an observed mean loss of 6 % whilst they started to feed themselves. Mean body-weight of juveniles just prior to commencing moult was 10.7 g. During active moult they increased by 0.9 g, declining again to a mean of 11.2 g on completion of feather growth. Both adults and juveniles reached their normal maximum body weight in January, and then lost weight in late winter and early spring. In autumn 1977, a period of exceptional Redpoll emigration from Britain, body weights of many individuals from a large flock in Kent were much higher than usual: several birds weighed over 16 g, suggesting pre-migratory fattening.(...)

Brett, J. R. & T. D. D. Gross (1979): Physiological Energetics in: Hoar, W. S., Randall, D. J. & J. R. Brett: Fish Physiology, pp. 280 - 352. Academic Press.

Buijse, A. D. & R. P. Houthuijzen (1992): Piscivory, Growth, and Size-Selective Mortality of Age 0 Pikeperch (Stizostedion lucioperca). Can. J. Fish. Aquat. Sci. 49: 894 - 902.

Busse, P. & W. Kania (1970): Operation Baltic 1961 - 1967. Methods of work. Acta orn. 12: 231 - 267.

Busse, P. (2000): Bird Station Manual. Gdansk 2000.

CP: This must be regarded as an up-to-date version of the Operation Baltic scale. The furculum alone separates "0" from "1" and "4" from "5". The liver shows in rankings 0 - 3, intestines in rankings 0 - 2, and there is an explicit comment by Busse. Mistakes are usually made when someone has a tendency to "liberal" interpretation of rules, e.g. when the bird has a thick cover of yellow fat on the belly but part of the intestinum visible; this should be "2" but is classified "3"(...)


Caldwell, L. D., E. P. Odum & S. G. Marshall (1963): Comparison of fat levels in migrating birds killed at a central Michigan and a Florida Gulf Coast television tower. Wilson Bull. 75: 428 - 434. Internetversion av denna uppsats.

Mean fat levels of six species of tropical-wintering thrushes, warblers, and vireos killed in the fall migration at a Florida Gulf coast television tower were significantly greater than in the same species killed at a central Michigan tower; levels in species believed to be habitual tram-Gulf migrants were more than twice as great in Florida. In constrast, fat levels in White-throated Sparrows, a species wintering in the Gulf states, were significantly greater in Michigan in the fall.
In spring, fat levels of four species breeding in Michigan were low to moderate and not significantly different at the two tower locations.
The results provide indirect evidence for the hypothesis that long-range northern migrants begin southward migration with low to moderate fat reserves and with consequent short flights, then increase their reserves with each stop until the maximum level is reached at or near points, as on or near the Gulf Coast, where long nonstop flights are undertaken.

Cloern, J. E. & F. H. Nichols (1978): A von Bertalanffy Growth Model with a Seasonally Varying Coefficient. J. Fish. Res. Board Can. 35: 1479-1482.


The von Bertalanffy model of body growth is inappropriate for organisms whose growth is restricted to a seasonal period because it assumes that growth rate is invariant with time. Incorporation of a time-varying coefficient significantly improves the capability of the von Bertalanffy equation to describe changing body size of both the bivalve mollusc Macotna baltllica in San Francisco Bay and the flathead sole, Hippoglossoides elassodon, in Washington state. This simple modification of the von Bertalanffy model should offer improved predictions of body growth for a variety of other aquatic animals.

Connell, C. E., E. P.. Odum & H. Kale (1960): The fat-free weight of birds. Auk 77: 1-9.


The fat-free weight, and also the lean dry weight, is relatively constant for birds of the same size (as indicated by wing length) and species in marked contrast to the total live weight which, in migratory species, fluctuates greatly because of the large variations in fat deposits. Accordingly, the amount of body fat of the living bird, or fresh specimen, may be accurately calculated by subtracting the fat-free weight (as a previously determined constant) from the live weight. Detailed analysis of fat-free weights of 230 Savannah Sparrows showed that sex, age, and racial differences were entirely the result of differences in basic body size as indicated by wing length. Postmigratory individuals, however, exhibited a lower fat-free weight than wintering or premigratory individuals of the same size. Fat-free weight values for males and females would provide the bird bander with a basis for a reasonably good estimate of the fat level. For a more precise estimate, fat-free weights would need to be worked out for each wing-length category, or else corrections made for individuals larger or smaller than average for the species. A table of fat-free and lean dry weights of 14 species of migratory birds is included.

Dalberg Petersen, F. (1972): Weight-changes at Hesselö in nightmigrating Passerines due to time of day, season and environmental factors. DOFT 66: 97-107.

1. In the springs og 1963, 1966 and 1971 several passerine species, especially Robins, were weighed at Hesselö. 2. All species investigated showed an increase in weight during the day. If the weight (Y) was expressed as a function of hours after sunrise (X) most distributions were better fitted by Y = a + b log X than Y = a + b X, where a and b are constants. 3. For the Robins the increase in weight is calculated for 3 different periods and compared with the rate of emigration. It is shown that the rate of emigration is largest when the increase in weight is largest, and vice versa. 4. The increase in weight is larger when the sky is clear than when the sky is covered by clouds. The number of birds present on the island has apparently no influence on the change in weight. 5. The mean weight of the Robins which leave the island is larger than the mean weight of the birds, which do not leave. 6. It is concluded that both innate and environmental factors influence the degree of emigration.

Davidson, N. C. (1982): Formulae for Estimating the Lean Weight and Fat Reserves of Live Shorebirds. Ring. & Migr. 4: 159 - 166.

Formulae for calculating the lean weight and fat reserves of shorebirds from their total body weight and wing-length and/or bill-length are given for six species wintering in Britain. General formulae for shorebirds in various seasons and areas are also given. The application of these, and other unpublished formulae, for estimating lean weight is discussed. Formulae derived from single species should be used whenever possible. A better estimate of lean weight is obtained from formulae using both wing-length and bill-length than from formulae using only one of these. The general formulae can be used when a single-species formula is not available.

Davidson, N. C. & P. R. Evans (1988): Preebreeding accumulation of fat and muscle protein by Arctic-breeding shorebirds.Proc. Int. Orn. Congr. XIX: 342 - 352.

Dolnik, V. R. & V. M. Gavrilov (1973): Caloric equivalent of body weight variations in chaffinces (Fringilla coelebs). In: Bykhovskii, B. E. ed. Bird migrations. Ecological and physiological factors: 273-287.

Direct measurements of energy value (caloric equivalent - CE) of nocturnal, daily (24-hour period) and seasonal variations in body weight were made. The size of nocturnal CE is related to the seasonal and individual state of energy reserves and their relationship during oxidation, and also to the amount of water lost by respiration. Dependences of nocturnal CE on the temperature of the surrounding medium in various seasons have been established. CE of weight increase in the course of 24 hours or any weight variation in the course of several days approximates in magnitude the caloric density of fat and does not depend either on the season of the year or temperature of the environment. CE of body weight decrease in the course of 24 hours is considerably lower and is affected by numerous factors. CE of variation of average body weight of birds within a population in one season (except for the period of breeding) is constant, but has different values at different seasons. Variations of body weight during the bird's transition from one seasonal state to another, and during breeding, possess no stable CE. CE of weight loss in flight is high, indicating an insignificant loss of water through respiration during flight. The results obtained make possible the determination of the energy equivalent of body weight variations of birds in the wild and under experimental conditions, with satisfactory accuracy. Analysis of factors which determine the variations in body weight, and the corresponding CE, are given.

Dolnik, V. R. & V. M. Gavrilov (1973): Energy metabolism during flight of some passerines. In: Bykhovskii, B. E. ed. Bird migrations. Ecological and physiological factors: 288-296.

Energy expenditure resulting from losses of body weight in flight, previously measured by the authors, is determined anew on the basis of additional experiments and calculations. Energy expended in flight amounts in house martins to 0.860±0.015 kcal/hour, in chaffinches - to 4.58±0.73, in bramblings - to 4.35±0.44, in siskins - to 2.52±0.33, in bullfinches - to approximately 5.67. Expenditure of energy during flight on physiological processes unconnected with flight is equal to the value of one standard diurnal metabolism, irrespective of the environmental temperature, i.e., a bird in flight is in a state of thermoneutrality.


Dowsett, R. J. & C. H. Fry (1971): Weight losses of trans-Saharan migrants. Ibis 113: 531 - 533.

Drent, R. H, Klaassen, M. & B. Zwaan (1992): Predictive growth budgets in terns and gulls. Ardea 80: 5 - 17.

Dunn, P. O., May, T. A. & M. A. McCollough (1988): Length of stay and fat content of migrant Semipalmated Sandpipers in eastern Maine. The Condor 90: 824 - 835.

Semipalmated Sandpipers (Calidris pusilla) stop at coastal staging areas in the Canadian maritime provinces and northeastern United States to replenish fat reserves before initiating a nonstop transoceanic flight of at least 3,200 km to wintering areas in South America. The relationship between estimated fat content at capture and length of stay (days between marking and last observation) of Semipalmated Sandpipers at one of these staging areas in eastern Maine was studied during 1980-1982. Total body mass and wing chord length were used to estimate fat content. When data were analyzed by week of initial capture, mean length of stay of both adults and juveniles decreased with increasing fat content. This supports the assumption that resumption of migration is affected by fat content at staging areas for long-distance nonstop flights. However, fat content at capture was a poor predictor of length of stay, which suggests that other factors are more important in determining length of stay.


Ehrenroth, B. & G. Ekbohm (1979): Weight and wing length variations in Long-tailed Tits Aegithalos caudatus during autumn movements in Central Sweden. In: Ehrenroth, B. Autumn movements in Parus and Aegithalos (Passeriformes) in central Sweden. Ph. D. thesis, Uppsala.

In 1969-1976 a total of 583 Long-tailed Tits were weighed and measured at Hammarö Bird Observatory. The mean weight of all birds was 8.6 g and the mean wing length 63.5 mm. The weight increased by 0.15 g per mm wing length. There were no significant differences in the size between birds trapped in different years. Seasonal differences in size were small, although birds trapped during a pentade in the middle of October i most years had, on avergae, shorter wing lengths than birds measured later. The daily mean weight increase was calculated to 0.76 g. On the basis of wide weight ranges within different wing length categories it is supposed that many birds were comparatively fat, with fat deposits between 1 and 2 g. An analysis of variance within and between flocks showed that birds within a flock were more alike than birds from different flocks.

Ehrenroth, B. & V. Marcström (1979): Autumn lipid levels in three species of tis, Parus montanus, Parus ater, Parus caeruleus, and Goldcrest Regulus regulus.. In: Ehrenroth, B. Autumn movements in Parus and Aegithalos (Passeriformes) in central Sweden. Ph. D. thesis, Uppsala.

Lipid and water levels of 20 Willow Tits, 21 Coal Tits, 15 Blue Tits and 31 Goldcrests collected during three autumns in Central Sweden were analysed. The Willow Tits posessed the lowest mean lipid level - 4.61 % of total weight - while the corresponding values for Coal Tits, Blue TIts and freshly killed Goldcrests were 7.2, 7.5 and 8.3 % respectively. The Blue Tits, which were found dead in nets, contained less water than expected. Highly significant differences in both fat and water levels were obtained between the Goldcrests collected alive and those found dead in the nets, indicating that the latter were in poor condition already when they arrived to the trapping area. A comparison of total weight data from the collected birds with maximum weights recorded for ringed birds indicate that some individuals of Coal Tits, Blue Tits and Goldcrests might reach lipid levels around 20 %, while the maximum fat content in Willow Tits probably does not exceed 15 %.

Ellegren, H. & T. Fransson (1992): Fat loads and estimated flight-ranges in four Sylvia species analysed during autumn migration at Gotland, South-East Sweden. Ring. & Migr. 13: 1 - 12.

The migratory capacity of four Sylvia species was investigated during their initial phase of autumn migration in Sweden. Fat loads of individual birds were estimated by first determining approximately the fat-free body masses for birds of different size (as judged from body mass - fat index relationships). Individual fat loads varied considerably both inter- and intra-specifically. The mean fat load (% fat mass of total body mass) of different species was: Lesser Whitethroat 9.3 %, Whitethroat 7.2 %, Garden Warbler 16.4 % and Blackcap 13.2 %. Comparatively low fat loads in the first two species may be because they probably commence their autumn migration in this area before the post-juvenile moult is completed. Our results indicate that several autumn migrating Garden Warblers and Blackcaps stopping over at Gotland have the energetic capability to almost cross continental Europe without refueling. This contrasts with the Whitethroat and the Lesser Whitethroat of which many individuals would only be able to cross the Baltic Sea.

Evans, P. R. (1966): Migration and orientation of Passerine night migrants in northeast England. J. Zool., Lond. 150: 319-369.

Evans, P. R. & P. C. Smith (1975): Studies of shorebirds at Lindisfarne, Northumberland. 2. Fat and pectoral muscle as indicators of body condition in the Bar-tailed Godwit. Wildfowl 26: 64-76.


Farmer, A. H. & J. A. Wiens (1999): Models and reality: Time-energy trade-offs in Pectoral Sandpiper (Calidris melanotos) migration. Ecology 80(8): 2566 - 2580.

We used a combination of modeling and field studies to determine the spring migration strategy of Pectoral Sandpipers (Calidris melanotos). We developed a dynamic programming model to predict patterns that should be detected along the migration route if Pectoral Sandpipers use a strategy of early arrival at the breeding grounds (time minimization) or arrival at the breeding grounds with excess energy reserves (energy maximization). The predictions were then compared to data collected at stopover sites in the mid-continent of North America and at the breeding grounds in Alaska over a 5-yr period (1992-1996).
During spring migration to their Arctic breeding grounds, Pewctoral Sandpipers stop periodically to feed. The length-of-stay at such stopovers, for both time minimizers and energy maximizers, was predicted to vary inversely with date and body fat, and to vary directly with invertebrate abundance. We observed that: (1) length-of-stay was negatively correlated with capture date in Missouri and Nebraska, but not in Texas; (2) length-of-stay was not correlated with body fat at any site; and (3) length-of-stay was positively related to invertebrate abundance at the Nebraska and Missouri sites. As the population moves northwards in the spring, three regional patterns are diagnostic of migration strategy. Length-of-stay was predicted to be bimodal (energy maximizer) or constant (time minimizer) with respect to latitude, but neither pattern was observed. The migration window, or period of time during which spring migrants occur, was predicted to decrease with increasing latitude for time minimizers, a pattern that was seen for both males and females. Body fat was predicted to increase with latitude for energy maximizers, a pattern that was seen for females but not males.
The evidence suggests that males and females differ in their spring migration strategies. Both sexes attempt to arrive in the Arctic as early as possible after ice breakup in the spring. Additionally, females gain significantly higher fat loads than males (up to 60 % body fat for females) during migration, and these energy reserves may later enhance female reproductive success. However, females gained large fat loads only during 1993 and 1995, which had above normal spring precipitation along the migration route. We believe that the correlation between female body fat and precipitation reflects an abundance of high-quality stopover habitat during wet springs. This view is supported by model sensitivity analyses showing that the spacing and quality of stopover habitat can strongly influence observed migration patterns. Our results suggest the need to focus additional research on the landscape-level features of the flyway through which shorebirds migrate.


Frelin, C. (1979): Physiological adaptations of blue tits (Parus caeruleus) to migration. Vogelwarte 30: 33 - 41.

Blue tits migrating through the Alps have moderate fat reserves mainly as oleate and palmitate. Their resting metabolism was estimated to 580 kcal/24 hours/kg. Respiratory quotients were low suggesting the utilization of fat reserves. The average theoretical flight range was estimated to 20 - 50 km. Ringing recoveries indicated that daily trips averaged 29 km. This suggests that fat reserves are just sufficient to support daily migratory flights. Additional energetic fuel may be obtained by feeding during migratory flights.
It is suggested that the physiological and metabolic mechanisms underlying migration in the Blue Tit are similar to those operating in typical migrant species. This physiological state was found stable whatever was the numerical importance of the migration.


Fry, C. H., I. J. Ferguson-Lees & R. J. Dowsett (1972): Flight muscle hypertrophy and ecophysiological variation of Yellow Wagtail Motacilla flava races at Lake Chad. J. Zool. 167: 293 - 306.


Gabrielsen, G. W, Klaassen, M. & F. Mehlum (1992): Energetics of Black-legged Kittiwake Rissa tridactyla chicks. Ardea 80: 29 - 40.
We compiled the energy budgets of Black-legged Kittiwake chicks in Kongsfjorden, Svalbard (79°N, 12°E), utilising (1) deuterium turnover rates to estimate food intake, (2) the doubly labelled water (D218O) method in conjunction with mass gain measurements and carcass analysis to determine energy requirements, and (3) laboratory assessed components of the nestling energy budget and production cost from mass gain measurements and carcass analysis. While (1) and (2) gave similar results we found that (3) underestimated the total energy expenditure by 13 - 21 %. This is explained by (3) neglecting the activity costs. During the first 15 - 16 days after hatching Kittiwake chicks are regularly brooded by the parents, resulting in a saving of 19 % of the metabolisable energy intake of the chick for this period. Beyond 16 days chicks live within the zone of thermal neutrality. The resting metabolic rate and the energy deposited as tissue (inclusive tissue synthesis) constituted 53 % and 24 % respectively, of the total energy budget over the entire nestling period. After 16 days, activity of the chicks increased considerably, making up 22 % of the total metabolisable energy intake. The main daily proportion of energy delivered to each chick raised is 33 % of the energy required by a pair of adult Kittiwakes. The parental investment in the inshore feeding Kittiwake is relatively high, in particular for pairs raising two chicks, when compared with offshore feeders.

Golley, F. (1961): Energy values of ecological materials. Ecology 42: 581 - 584.
Greenwood, J. J. D. (1992): Viewpoint. Fat Scores: a statistical observation. Ring. & Migr. 13: 59 - 60.
(from text) In a sample of Palaearctic migrants caught in Senegal in spring, Loske (1990) found that species in which the mean fat score was high tended to have less variation in fat score than those in which mean fat score was lower. He suggested biological explanations for this. It is, however, possible that the correlation is a by-product of the fact that the scale of fat scores has a maximum.(...)

Gudmundsson, G. A., Lindström, Å & T. Alerstam, (1991): Optimal fat loads and long-distance flights by migrating knots Calidris canutus, sanderlings Calidris alba and turnstones Arenaria interpres. Ibis 133: 140-152.

Arctic waders often build up large fat loads and complete their migration journeys by a few long-distance flights between traditional staging sites. Optimal fat loads and choices of staging sites differ depending on whether the birds are adapted to minimize energy or time spent on migration. In the latter case, we predict that the birds will depart for the next staging site when the instantaneous speed of migration expected after arrival at the next site, exceeds the corresponding speed at the departure site. The instantaneous migration speed is a function of the rate of fat deposition and the current fat load. As a consequence of this, overloading (birds deposit larger fat loads than needed merely for covering the flight distance to the next destination) and by-passing of possible, but low-quality staging sites, are expected under specific conditions in time-selected migration.
Estimates of fat deposition rates and departure fat loads were obtained by captures of Knots Calidris canutus, Sanderlings C. alba and Turnstones Arenaria interpres in W. Iceland during spring migration. Further fat deposition data referring to spring migration of these species were compiled from the literature. Fat deposition rates at different sites, as measured by the daily gain in mass relative to lean body-mass, range between 1.0 and 3.6 %/day, and departure fuel-loads (in % of lean body-mass) between 27 and 73 %.
Comparison with flight range estimates suggests that overloading may be a regular phenomenon during spring migration of Knots, Sanderlings and Turnstones: Furthermore, fat deposition rates at different staging sites, and the general difference in migration patterns between spring and autumn, indicate that by-passing of possible staging-sites may well occur. Hence, it cannot be excluded that the waders' migratory habits primarily serve to maximize the overall speed of migration.



Harris, M. P., Wanless, S. & A. Webb (2000): Changes in body mass of Common Guillemots Uria aalge in southeast Scotland throughout the year: implications for the release of cleaned birds. Ring. & Migr. 20: 134 - 142.

Body masses of Common Guillemots in southeast Scotland showed a pronounced annual cycle with birds being consistently heavier during the moult and over the winter. On average, adults were significantly heavier than immatures and males tended to be heavier than females. Masses of both breeding adults and immature birds declined during the breeding season. Comparisons of the body masses of wild birds and those released from rescue centres after treatment and cleaning, indicated that the latter were about 30 % lighter, a difference which might explain why the survival prospects of such birds are currently so poor. The problems associated with setting target release masses for Guillemots are discussed.

Hart, J. S. & M. Berger (1972): Energetics, water economy and temperature regulation during flight, pp. 189 - 199 in Voous, K. H. (ed.) Proc. XVth Int. Orn. Congr. The Hague.

Haukioja, E (1969): Weights of Reed Buntings Emberiza schoeniclus during summer. Ornis Fennica 46: 13-22.

Hedenström, A. & Å. Lindström (1990): High body masses of migrating Wrynecks Jynx torquilla in southern Sweden. Vogelwarte 35: 165 - 168.

We have studied body masses and visual fat depots of Wrynecks (Jynx torquilla) at stopover sites in South Sweden. Most of the birds were trapped at Ottenby Bird Observatory. Especially in autumn some birds were very fat and estimated average fat depots were higher than the average for passerines in similar migratory conditions. The large fat depots, together with the recovery pattern of Swedish ringed Wrynecks, indicate that individuals of this species migrate over the European continent in one or only a few long flights.

Hedenström, A. (1992): Flight performance in relation to fuel load in birds. J. Theor. Biol. 158: 535 - 537.

Hedenström, A. & S. Sunada (1999): On the aerodynamics of moult gaps in birds. J. Exp. Biol. 202: 67-/76.

During the moult, birds sequentially replace their flight feathers and thus temporarily have gaps in their wings. These gaps will vary in size and position(s) during the course of the moult. We investigated the aerodynamic effects of having moult gaps in a rectangular wing by using a vortex-lattice (panel) approach, and we modelled the effect of moult gap size at the wing moult initiation position, of gap position in the primary tract and of two simultaneous gaps (as occurs during secondary feather moulting in many birds). Both gap size and gap position had a detrimental effect on aerodynamic performance as measured by lift curve slope, effective aspect ratio and the aerodynamic efficiency of the wing. The effect was largest when the moult gap was well inside the wing, because the circulation declines close to the wing tip. In fact, when the gap was at the wing tip, the performance was slightly increased because the lift distribution then became closer to the optimal elliptical distribution. The detrimental effect of moult gaps increased with increasing aspect ratio, which could help to explain why large birds have relatively slow rates of moult associated with small gaps.

Hedenström, A. & M. Rosén (2001): Predator versus prey: On aerial hunting and escape strategies in birds. Behav. Ecol. 12: 150-/156.

Predator and prey attack-escape performance is likely to be the outcome of an evolutionary arms race. Predatory birds are typically larger than their prey, suggesting different flight performances. We analyze three idealized attack-escape situations between predatory and prey birds: climbing flight escape, horizontal speeding, and turning and escape by diving. Generally a smaller bird will outclimb a larger predator and hence outclimbing should be a common escape strategy. However, some predators such as the Eleonora's falcon (Falco eleonorae) has a very high rate of climb for its size. Prey species with an equal or higher capacity to climb fast, such as the swift Apus apus, usually adopt climbing escape when attacked by Eleonora's falcons. To analyze the outcome of the turning gambit between predator and prey we use a Howland diagram, where the relative linear top speeds and minimum turning radii of prey and predator define the escape and danger zones. Applied to the Eleonora's falcon and some potential prey species, this analysis indicates that the falcon usually wins against the example prey species; that is, the prey will be captured. Level manoeuvering hunting is the most common strategy seen in Eleonora's falcons. To avoid capture via use of this strategy by a predator, the prey should be able to initiate tight turns at high linear speed, which is facilitated by a low wing loading (weight per unit of wing area). High diving speed is favoured by large size. If close enough to safe cover, a prey might still opt for a vertical dive to escape in spite of lower terminal diving speed than that of the predator. On the basis of aerodynamic considerations we discuss escape flight strategies in birds in relation to morphological adaptations.

Helms, C. W. & W. H. Drury (1960): Winter and migratory weight and fat field studies on some north american buntings. Bird-Banding 31: 1-40.

(...)2. During the winters of 1956-57 and 1957-58, weight and fat determinations were made on 477 Tree Sparrows, Spizella arborea (over 2000 records), and 572 Slate-coloured Juncos, Junco hyemalis (nearly 1000 records). The stable winter populations of both winters were about 6o Juncos and 50 Tree Sparrows. These were color banded and followed during the winter and through spring migration. The units were groups of 4-8 birds which usually traveled together for the whole winter.
3. Mean winter weights of Tree Sparrows both winters was 20.22 g, S.D. 1.56 g, and of Slate-colored Juncos 21.16 g, S.D. 1.92 g. Diurnal weight variation in Tree Sparrows was 7.3-9.8 %, and in Juncos 9.9-11.2 %. Daytime weight and fat increases were balanced by overnight loss. About one-half of this daily variation is attributable to fat, and the other half to ingested food. Diurnal variation is greater during mid-winter in both species.
(...)7. Weight and fat variation becomes temperature independent during migratory periods in both species. Although only the Junco shows a significant migratory weight peak in spring, the temperature independence of weight during migratory periods in both species suggests that different physiological controls associated with migration become operative at migratory periods. These controls remain unknown. (...)

[CP] This is history as well, but the paper is transparent and can be used.


Hilton, G. M., Furness, R. W. & D. C. Houston (1980): A comparative study of digestion in North Atlantic seabirds. J. Avian Biol. 31: 36 - 46.

We present data on digestive efficiencies and gut retention times of eight North Atlantic seabird species, fed on two fish species - lesser sandeel Ammodytes marinus and whiting Merlangius merlangus- which commonly occur in the diet of wild seabirds. In an interspecific comparison, there was a positive relationship between retention time and digestive efficiency, which we suggest represents a trade-off between conflicting benefits of efficient digestion and rapid digestion. Analysis of excretion curves revealed that retention time of digesta in the stomach was more important than passage time of digesta through the intestine in determining whole gut retention time. Differences in stomach retention time of lesser sandeel and whiting explained the longer overall retention time of the latter diet. Stomach retention time and whole gut retention time were greater in species with relatively large stomachs, while intestine passage time was correlated with relative intestine length. Species which typically eat a wide range of food types, including low quality items, tended to have slow and efficient digestion and heavy stomachs, whereas species which specialise on readily digestible and energy dense food types had the opposite digestion strategy.

Hope Jones, P. (1980): Wing lengths and weights of spring Wheatears Oenanthe oenanthe at Bardsey, Gwynedd. Ring. & Migr. 13: 162 - 166.

An analysis is made of wing lengths and weights of 141 male and 127 female Wheatears caught on Bardsey in the spring of years 1970 - 1989. (...)Weights ranged 21 - 46 g in males and 19 - 44 g in females. Time of day did not affect greatly the median weights, but medians for May were 8 g higher (males) and 5 g higher (females) than in March. It is concluded that Bardsey frequently intercepts the passage of Greenland/Iceland Wheatears in spring, though the proportions from these two destinations is not yet known.

Houston, A. I, MacNamara, J. M. & J. M. C. Hutchinson (1993): General results concerning the trade-off between gaining energy and avoiding predation. Phil. Trans. R. Soc. Lond. B 341: 375 - 397.

Houston, A. I, Welton, N. J. & J. M. MacNamara (1997): Acquisition and maintenance costs in the long-term regulation of avian fat reserves. Oikos 78: 331 - 340.

Hussell, D. J. T. & A. B. Lambert (1980): New estimates of weight loss in birds during nocturnal migration. Auk 97: 547-558.

Weight loss during flight was estimated for 10 species of passerines of body weight 8 - 32 g, using a refinement of the method described by Hussell (1969). Analysis of 2,226 migrants, weighed after they were attracted to the Long Point lighthouse, Ontario during nocturnal flight, yielded a mean weight loss of 0.70 % of body weight/h. Excluding the Blackpoll Warbler, which had a substantially lower rate of weight loss than any other species, mean weight loss was 0.91 % of body weight/h. In this reduced group of 9 species, weight loss averaged about 62 % of the rate of fat utilization predicted by Berger and Hart's (1974) flight metabolism data.


Johnson, C. (1985): Patterns of Seasonal Weight Variation in Waders on the Wash. Ringing & Migration 6: 19-32.

Analysis of weight variation, based on monthly mean weights for ten wader species occurring on the Wash demonstrating the patterns of season weight variation. For each species the trends are interpreted in terms of adaptations and responses to specific life cycle events and potential feeding difficulties which arise from winter environmental conditions.

Johnson, O. W. & M. L. Morton (1976): Fat content and flight range in shorebirds summering on Enewetak Atoll. Condor 78: 144 - 145. Internetversion av denna uppsats.

Johnson, O. W. & M. L. Morton, P. L. Bruner & P. M. Johnson (1989): Fat cyclicity, predicted migratory flight ranges, and features of wintering behavior in Pacific Golden Plovers. Condor 91: 156 - 177.

Annual cyclicity of body components in wintering Pacific Golden Plovers (Pluvialis fulva), combined with ecological and behavioral features were variously studied from 1978 through 1987. The primary research site was in Hawaii at the Bellows Air Force Station (BAFS), Oahu. After fall arrival, body weights trended downward for several weeks, possibly in response to the energy required for the behaviors associated with establishing (and reestablishing) residency combined with molting. Major premigratory weight gains began in late March about 1 month prior to migration. Statistical correlations between body weight and fat content are described. Premigratory dehydration as an adaptation to increase flight range and/or energy stores at the migratory destination was likely.
Fat-free dry weights (FFDW) at BAFS were least in the fall and greatest in the spring. For juveniles, this difference relates to overall body growth during the first wintering season. With older birds, it may reflect the environmental conditions at the respective end points of migration - predictably favorable for southbound migrants, unpredictable for northbound birds. Plovers wintering on Enewetak Atoll and wake Island had significantly higher FFDWs than the birds at BAFS. Possible factors in this relationship are discussed.
The BAFS population contained many territorial birds, and showed high rates of survival and site fidelity over successive years. Juveniles arriving on the wintering grounds for the first time probably experience considerable mortality as they compete with established adults for space and resources. Based on wing lengths, many of the plovers involved in this study were from Alaska breeding grounds. Flyways to the tundra may involve staging areas, but specific information is lacking. Using current formulae, we describe the relationship between body weight and flight range, and provide estimates of the fat required to reach various landfalls.

Johnston, D. W. & R. W. McFarlane (1967): Migration and bioenergetics of flight in the Pacific Golden Plover. Condor 69: 156 - 168. Internetversion av denna uppsats.

Movements, population fluctuations, and other migratory aspects of the Pacific Golden Plover were observed on Wake Island periodically between June 1963 and May 1965. Optimal habitat for plovers on the island included grassy areas beside the air strips and the sand and mudflats bordering a large lagoon. Northbound migrants became especially conspicuous in late April, and southbound migrants evidently began arriving on the island in late July or August. A significant number of the plovers overwinter on Wake Island where they establish territories; yet during the autumn and spring daily variations in numbers indicated much inter-island movement.
Periodically, samples of plovers were collected for studies of molt, body weight, and lipid extractions. In 1964 27 birds were taken in April, 11 in August, and 12 in December. An additional two birds were taken alive in a mist net for measurement of basal rate of metabolism. Both the April and August migrants were molting body feathers; molting primaries were detected in August (and a few December) birds. Thus, our data do not confirm the contention of Henshaw that Golden Plovers in the spring molt before they migrate or, in the autumn, migrate before they molt. Among the December birds sparse body molt was noted, but some were still molting primaries and rectrices.
On the average the April birds weighed more (153 g) than the August (133 g) and December birds (130 g). Maximum weights in April were 192.1 and 190.5 g. Despite these average body weight differences, the average body lipids in April and August were similar (26.5 and 22.8, respectively). Lipid contents amounted to a maximum of 180 per cent of the nonfat dry weight, a value which is considerably less than that obtained by other workers for small migrating passerines. Basal rate of metabolism was found to be 0.0047 kcal/g-hr. at 31" C. Flight speed for the species is believed to be about 65 mph, and we assume, from the investigations of LeFebvre, that flight energy expenditure is eight times the basal rate. Thus the fattest (by extraction) plovers in April had an estimated flight range of about 6200 miles; those in August, 5900 miles; and those in December, 2500 miles. Our combined data also indicated that only a plover containing at least 18 g of lipids and weighing about 150 g will attempt the 2400-mile flight from Wake Island to the Aleutian Islands or Kamchatka Peninsula, or vice versa. Plovers arriving on Wake in the autumn from the north still contained, on the average, 22 g of lipids.
Details of migration in the American race of the Golden Plover are also discussed and re-examined. We believe, contrary to earlier estimates, that if these birds do fly nonstop from Nova Scotia to South America, they accomplish the flight in some 37 hours and consume only about 18 g of lipids.


Kaiser, A. (1993): A new multi-category classification of subcutaneous fat deposits in songbirds. J. Field Orn. 64: 246-255.

A new fat scoring technique for small birds is introduced using 31 classes (nine main classes with up to four subclasses each; Fig. 1). In contrast to many othe methods, fat score and respective fat load (as determined by the Soxhlet method) correlate very well. Furthermore, variability in the calculated regression lines for nine different species is low. This effective new method can easily be learned by handling approximatively 100 individual birds and substantially improves precision of studies on fat-deposition in migratory birds.

Kaiser, A. (1993): A new multi-category classification of subcutaneous fat deposits in songbirds. J. Field Orn. 64: 246-255.

Karlsson, L., K. Persson, J. Pettersson & G. Walinder (1988): Fat-weight relationships and migratory strategies in the Robin Erithacus rubecula at two stop-over sites in South Sweden. Ring. & Migr. 9: 160 - 168.

Karltun, E. (1981): Vikter hos tofsvipor som dött av svält. Vår Fågelvärld 40: 111 - 112.


Khoury, F. (2004): Seasonal variations in body fat and weight of migratory Sylvia warblers in central Jordan. Vogelwarte 42: 191 - 202.

The physical state of Sylvia warblers stopping over in a large plantation on the edge of the eastern desert of Jordan was studied during spring and autumn migration. Sylvia species caught in autumn had generally higher fat loads than in spring, which can be attributed to common aspects of migration habitats. However, variations in strategies of different species were indicated by different distributions of fat scores and physical changes during stopping over. In spring, Blackcaps stopping over replenished their fat reserves, possibly as preparation for crossing further desert areas in the Middle East. Several Lesser Whitethroats stopped over in spring without replenishing fat reserves. Thus their choice of a suitable site with low predation risk was probably to recover water balance and/or muscle tissue after crossing the Sahara. It is moreover assumed that Lesser Whitethroats are able to gradually cross open deserts of the Middle East where they may feed en route in spring. Many Garden Warblers stopped over without replenishing fat reserves but with a significant increase in body mass, which indicated recovery of water balance and/or muscle tissue. Garden Warblers were not recorded in open desert areas, thus they are believed to avoid further desert and migrate gradually nothwards along more fertile areas of the Middle East, where they feed en route. In autumn, most birds had high fat loads, but leaner Blacjcaps and Lesser Whitethroats were frequent, some of which were found to stop over and replenish fat reserves, apparently in preparation for crossing the Sahara. Variations in migration patterns among closely related long distance migrants are especially evident after crossing the Sahara in spring, and might reflect different migration strategies.

Klaassen, M., Kersten, M. & B. J. Ens: (1990): Energetic requirements for maintenance and premigratory body mass gain of waders wintering in Africa. Ardea 78: 209 - 220.

Daily food intake, assimilation efficiency and body mass were monitored in five species of waders kept in cages under tropical conditions. In three of these species the daily energy expenditure was measured using the doubly labeled water method. The energy content of the deposited reserve tissue depended on the condition of the birds, since the energy required for body mass gain was low in lean birds and high in fat birds. Maintenance metabolism was relatively low compared to wader species wintering in temperate regions. This phenomenon is suggested to be an adaptation towards reduced endogenous heat production, which may help in avoiding heat stress under tropical conditions. The reduced endogenous heat production hypothesis was supported by the finding that assimilation efficiencies of the tropical birds were low, which might have been caused by a reduced protein assimilation resulting in a relatively low heat increment of feeding. More direct support was the reduction in maintenance metabolism of Turnstones from the popular wintering in Africa compared to the maintenance metabolism of Turnstones from the population wintering in Europe, measured when the two groups were kept under identical conditions.

Klaassen, M & R. H. Drent: (1991): An analysis of hatchling resting metabolism; in search of ecological correlates that explain deviations from allometric relations. Condor 93: 612 - 629. Internetversion av denna uppsats.

From data in the literature, an allometric equation is compiled for hatchling resting metabolic rate and an attempt is made to explain residual variation in terms of hatchling type, yolk and water content, embryonic and postnatal growth rate, and environ- mental circumstances (latitudinal distribution). The body mass exponent for resting metab- olism in hatchlings was 0.86 and, thus, substantially different from the values compiled for adult birds (0.67475). Relatively high hatchling metabolic rates were found for birds exhibiting high embryonic and postnatal growth rates, as well as for those species that hatched at high latitudes. A functional explanation is postulated for the correlations between hatchling metabolism and these three variables.

Klaassen, M. & C. Beech (1992): Resting and peak metabolic rates of Arctic Tern nestlings and their relations to growth rate. Physiol. Zool. 65: 803 - 814.

Klaassen, M., Zwaan, B., Heslenfeld, P., Lucas, P. & B. Luijckx (1992): Growth rate associated changes in the energy requirements of tern chicks. Ardea 80: 19 - 28.

To obtain information on the energetic implications of intraspecific growth rate differences we measured the energy requirement for development in chicks of Common Tern Sterna hirundo and Sandwich Tern S. sandvicensis under laboratory conditions. Both maximum (kJ/day) and total gross energy intake for development (kJ during prefledging period) increased with growth rate and were reduced by almost 40 % and 25 % %, respectively, in the slowest compared to the fastest growing individuals in each of the two species. These results imply that the range of food availability within which a chick can grow to adulthood is wider than hitherto believed. However, one should bear in mind that slow growth also may result in higher nestling and postfledging mortality.

Klaassen, M., Habbekotté, B., Schinkelshoek, P., Stienen, E. & P. van Tienen (1992): Influence of growth rate retardation on time budgets and energetics pf Arctic Tern Sterna paradisaea and Common Tern S. hirundo chicks. Ibis 136: 197 - 204.

Time-budgets of free-living chicks of Arctic Terns Sterna paradisaea and Common Terns S. hirundo throughout development are presented with special reference to changes in time allocation when growth rate varies. Chicks of both species were inactive most of the time observed (87 %). Time allocated to the different behaviours changed during development and was generally better correlated with body mass than age. Slower growing nestlings were brooded more and allocated more time to quiescence and less time to locomotion, preening, begging and attacking (the latter two significant only for the Arctic Tern). The energetic implications of variation in time budgets with age and growth rate were considered. Parental brooding resulted in an average energy saving of nearly 40 % of an individual nestling's thermoregulatory costs. Whereas thermoregulatory costs remained nearly unchanged in Arctic Tern chicks, these were negatively correlated with growth rate in Common Terns. Tentatively, we estimated a 30 % reduction in a nestling's total energy requirement for a 50 % reduction in average growth rate for borth species.

Klaassen, M. (1995): Water and energy limitations on flight range. Auk 112: 260 - 262. Internetversion av denna uppsats.

Klaassen, M. (1996): Metabolic constraints on long-distance migrations in birds. J. Exp. Biol. 199: 57 - 64.

Klaassen, M. & Å. Lindström (1996): Departure fuel loads in time minimising migrating birds can be explained by the energy costs of being heavy. J. Th. Biol. 183: 29 - 34.

Kvist, A., Lindström, Å., Green, Piersma, T. & G. H. Visser (2001): Carrying large fuel loads during sustained bird flight is cheaper than expected.. Nature 413: 730-732.

Birds on migration alternate betweem consuming fuel stores during flights and accumulating fuel stores during stopovers. The optimal timing and length of flights and stopovers for successful migration depend heavily on the extra metabolic power input (fuel use) required to carry the fuel stores during flight. The effect of large fuel loads on metabolic power input has never been empirically determined. We measured the total metabolic power input of a long-distance migrant, the red knot (Calidris canutus), flying for 6 to 10 h in a wind tunnel, using the doubly labelled water technique. Here we show that total metabolic power input increased with fuel load, but proportionally less than the predicted mechanical power output from the flight muscles. The most likely explanation is that the efficiency with which metabolic power input is converted into mechanical output by the flight muscles increases with fuel load. This will influence current models of bird flight and bird migration. It may also help to explain why some shorebirds, despite the high metabolic power input required to fly, routinely make nonstop flights of 4,000 km or longer.

Kvist, A. & Å. Lindström (2001): Basal metabolic rate in migratory waders: intra-individual, intraspecific, interspecific and seasonal variation. Functional Ecology 15: 465-473. Internetversion av denna uppsats.

  1. Basal metabolic rates (BMR) were measured in 36 adult and 119 juvenile waders of 19 species on autumn migration in southern Sweden.
  2. In a comparison with literature data, it was found that juvenile BMR was generally lower than at the onset of migration in the Arctic and slightly higher than on African wintering grounds.
  3. The seasonal differences may reflect local physiological adaptations or possibly a gradual decline from high premigratory levels due to growth. Our data contradict the idea that BMR is high during migration as an adaptation to generally high levels of energy expenditure.
  4. The allometric exponent, scaling BMR to body mass, was significantly higher within individuals (1.19) and within species (1.82) than among species (0.62).
  5. The high intra-individual exponent indicates that non-fat tissues, with a high metabolic activity, are involved in the mass changes during migratory stopover.
  6. The high intraspecific exponent indicates that tissues with a high metabolic activity contributed disproportionately to variation in body mass among individuals or that larger individuals had elevated mass specific metabolic rates of some tissues.


Kvist, A. & Å. Lindström (2003): Gluttony in migratory waders - unprecedented energy assimilation rates in vertebrates. Oikos 103: 397 - 402.

Maximum energy assimilation rate has been implicated as a constraint on maximal sustained energy expenditure, on biomass production, and in various behavioural and life history models. Data on the upper limit to energy assimilation rate are scarce, and the factors that set the limit remain poorly known. We studied migratory waders in captivity, given unlimited food supply around the clock. Many of these waders assimilated energy at rates of seven to ten times basal metabolism, exceeding maximum rates reported for vertebrates during periods of high energy demand, for example during reproduction and in extreme cold. One factor allowing the high energy assimilation rates may be that much of the assimilated energy is stored and not concomitantly expended by muscles or other organs. The remarkable digestive capacity in waders is probably an adaptation to long and rapid migrations, putting a premium on high energy deposition rates. The upper limit to daily energy assimilation in vertebrates is clearly higher than hitherto believed, and food availability, total daily feeding time and, possibly, the fate of assimilated energy may be important factors to take into account when estimating limits to energy budgets in animals.

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