Lesser Redpolls (1 August 2005)
Two Lesser Redpolls Carduelis cabaret mist-netted together at Woolston turned out to be a breeding pair, giving a great opportunity to compare the plumage of the sexes:
The female is on the left, in case it needed stating! However, not all birds are as easy to sex as these - first-year males have been reported without any red except on the crown - and confirmation from a brood patch or cloacal protuberance is advisable. These finches are very similar to their close relative, the Linnet, shown previously on these pages. The rump colour can also be helpful:
The image above also shows clearly the red poll (head) from which they take their common name.
It can be trickier to age redpolls than most other finches. British birds seldom show a moult limit in the greater coverts, and tail shape is a key criterion. In this species, as shown by Svensson's Identification Guide to European Passerines, their tails are often more pointed than those of many other birds, so we have to become used to their 'normal' shape: a typical adult shape in a redpoll would equate to first-year rectrices in, for instance, Chaffinches. I cannot show a comparison here because both of these birds are Euring age code 6 (after-second-year birds), hatched in 2003 or earlier.
The wings are also useful for ageing. Recalling the moult strategy of this species - a full moult of wings and tail in the birds' second year of life, after the breeding season - second-year birds (Euring age code 5) would still have the flight feathers with which they left the nest a year ago, and these would be obviously worn. The photographs below show the wings of both birds to be in very good condition. The male had only recently started moulting, and the female had not yet dropped any old feathers:
There is an extra clue to ageing in the wing of the female bird: she has one secondary feather (s2) - on the right wing only - that had not been replaced in her moult last year, and is now very abraded, having had to last for two (or more) years. The presence of two generations of remiges means that she must have gone through at least one full moult, and thus has to be at least in her third calendar year of life. The old secondary feather is especially depicted in the image below:
Typically of the seed-eating species, Lesser Redpolls tend to breed late. I ringed a brood of Lesser Redpolls at Woolston on 24 July in 1993, so the beginning of August is not a surprising date for them still to be in breeding condition. Consequently, they moult late: indeed, according to the BTO Moult Guide (H. B. Ginn and D. S. Melville. Moult in Birds. BTO Guide No. 19, 1983) this male is among the earliest recorded at that stage of primary moult (321107).
Finally, it is difficult to discuss redpolls without consideration of the species or race. Until January 2001, these birds would have been assigned to the cabaret race of the Redpoll Carduelis flammea cabaret. At that date, the British Ornithologists' Union Records Committee decided that it should be 'split' from Mealy Redpoll Carduelis flammea flammea, and Lesser Redpoll Carduelis cabaret is now a separate species from Common Redpoll Carduelis flammea. The British Ringing Committee recognises that some redpolls might not be specifically identifiable, using species codes of LESRE (Lesser Redpoll), COMRE (Common Redpoll), ARCRE (Arctic Redpoll Carduelis hornemanni) and REDPO (not specifically determined redpoll). Only Lesser Redpolls breed in Britain, however, so that problem should only present itself with visiting birds.