Adult Tringa starting to moult in Sweden

It is a well-known fact, that Scandinavian breeding-birds of many wader species, e.g. Snipe Gallinago gallinago and Ruff/Reeve Philomacus pugnax will migrate with growing or fresh inner primaries (P1 - 6). A well-known fact from an oral tradition, since very little has been written about wader moult, and much older material seems to be lost. When it comes to other species, particularly larger Tringa, opinions differ, partly because most birds caught at ringing stations have been juveniles. The tacit assumption seems to be that most species have a Wood Sandpiper pattern (Hoffmann 1957), i.e. they fly with old remiges to particular moulting grounds in W. or S. Europe and start moulting there. (Still, thousands of adult Redshanks and Wood Sandpipers must have been handled by Swedish ringers between 1960 and 1979, and we know that ongoing and suspended moult was recorded among these birds - where are the records? Is there e.g. anyone who knows the whereabouts of the note-books containing all wader-ringings at Skanör between 1964 and 1975?)

This note is intended to be a beggar's letter, but a beggar should achieve something, make some kind of performance, in order to merit his reward, the thing he is asking for. We are asking for moult cards on adult Tringa from Scandinavia, we want to see already existing material, and it should preferably be in the following form:

• Wood Sandpiper, 2c(alendar)+, Foteviken (55.27 N, 13.00 E) 890722. P1 - 6 fresh, from P7 old. S1 - 2 fresh, from S3 old.
  
• Greenshank, 2c+, Foteviken 970828 (Weight: 193 g). P1 - 5 fresh, P6 0.8, from P7 old. S1 0.7, S2 0.4, from S3 old.
  
• Redshank, 2c+, Foteviken 980803 (Weight: 138 g). P1 - 5 fresh, P6 0.9, P7 0.7 P8 pin, from P9 old. S1 - 2 0.9, S3 0.6, S4 0.5, S5 - 6 pins, from S7 old. This bird was a breeding bird, retrapped at the same site 1.5.2001 (weighing 160 g; probably a female carrying egg. And wing-length 167 mm - dangerously close to the robusta limit). 160 grams, too much for a nominate bird even if it was breeding - what if it was migration fat? I hear bells ringing. Could this bird have been a late / early robusta? I didn't ring it myself, and I didn't look particularly at the plumage when the bird was retrapped by midnight. A Redshank is a bit of a nuisance when you catch Dunlin, you want to get rid of it, especially if you think that you caught a brooding bird. As far as I (did) know, all robusta have left Scania by April 10th, when breeding birds arrive, and they do not mix with breeding birds in breeding habitats, they stick to wrack beds and wind flats in late March and April. On the other hand moulting Calidris alpina alpina mix with breeding C. a. schinzii at the same site in May... What goal area is to that extent Arctic or semi-Arctic that it remains unavailable until May? Central or even North Iceland.
  
  Additions 8.8.02, 27.7.04: CP
  
  
• Redshank, 2c+, Skanör 020808 (Wing: 165 mm, weight: 148 g). P1 - 3 fresh, P4 0.9, P5 0.7, P6 pin = 0.3; R1 0.5, 10 old tail-feathers; 20 % new great, median and small coverts, under tail-coverts growing. This bird had wing-length (worn wing) 165 mm, bill 40.2 mm, grey suffusion on breast and large V-shaped spots along sides, it was compact and stout, rich in contrast, looking like a perfect robusta to me, very distinct from the Scanian breeding type. I have looked through my Redshank biometry from July and August; it is possible that robusta, adult as well as juvenile, should be looked for as early as 15 July. Like (some) Dunlin they spend little more than 2 1/2 months of the annual cycle on breeding-grounds, and the moult in turn is of the same duration. One bird hade P9 and P10 0.8 on September 14th, tail and secondaries fresh; if the whole moult had been performed in the Sound area it must have arrived in early July. New material is added all the time, however, moulting robusta are a common occurrence in south Scania in July:
• Redshank, 2c+, Skanör 040727 (Wing: 170 mm, weight: 158 g). P1 - 2 fresh, P3 0.9, P4 0.7, P5 0.5, P6 pin = 0.1; no other remex shed. The flying ability of this bird was slightly impaired, and breeding Hobby Falco subbuteo was hunting at the site; the Redshank walked and swam as much as possible. It had a young bird in company, caught as well; on 28.7 I watched a similar couple: 2c+ + 1c Greenshank, and both were caught together, the adult Greenshank not moulting. I believe it is rather common for juvenile Tringa to accompany one parent on the first stages of migration, maybe rule rather than exception. A case for blood-sampling and genetics: "target" suspected parents + offspring and draw some blood, such study will contribute to our knowledge of the juvenile migration strategy. As a matter of fact I believe that even many early Dunlin juveniles are attached to one true parent on migration in the Baltic area. [CP]

"Moult in Birds" (Ginn & Melville 1983) opens its wader chapter with the following statement: Waders typically shed P1 - P5/P6 more or less simultaneously, P6/P7 is then dropped when the inner primaries are nearly full-grown and the rest of moult is more leisurely. This is also the underlying pattern in the three cases presented above; the Wood Sandpiper had suspended after P6 and would probably resume its moult at some site in the Mediterranean, while the Greenshank most probably was going to suspend before continuing its migration journey. These two individuals have performed the "critical" part of their remige moult on Scandinavian breeding grounds, and at least the Greenshank must have been conducting young as well. But the Redshank is still more impressive, it has exchanged c. 80 per cent of remiges in Sweden and is confronted with two seemingly equal options: to suspend after P8 and migrate, or to complete its moult before migrating. (According to Ginn & Melville (1983) 1 % of the Redshanks arrive on the Wash in suspended primary moult.)

It should be added, that the four birds presented here are extreme cases. Most adult Wood Sandpipers do not moult remiges in Sweden, a handful of investigated adult Greenshanks had not started, and we have looked at a score of adult Redshanks in July / August without finding signs of moult. One possibility is that the birds starting to moult in Scandinavia are mainly birds in their second calendar year, carrying very worn remiges from the first feather generation. The weight of the Greenshank as well as of the Redshanks - 1 - 2 s.d. above the mean value - demonstrate that a moulting individual of these two species need not worry about its energy budget in the Öresund area; there is food enough for moult.

Now, to the reader of this note: how far to the north are there records of moulting Tringa in Scandinavia?

The moult cards were recorded by Peter Olsson, the note written by Christer Persson, published on the web on 30.10.98, addendum 8.8, 12.8.02. 1.8.04.