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Carduelis Hornemanni Exilipes: an Identification Review Based on the 1995/96 Influx

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Carduelis Hornemanni Exilipes: an Identification Review Based on the 1995/96 Influx R. Johnson Arctic Redpoll Carduelis hornemanni exilipes: an identification review based on the 1995/96 influx S. C.Votier, J. Steele, K. D. Shaw and A. M. Stoddart he identification of Arctic Redpolls tion exhibited by redpolls, we have drawn Carduelis hornemanni has been on the huge resource of information gath- Texhaustively covered, and the main ered together in the form of the highest- criteria used to separate them from Common quality submissions of records to the British Redpolls C. flammea have been well Birds Rarities Committee (BBRC). In order to described (Lansdown et al. 1991; Stoddart illustrate the plumage variation and key fea- 1991; Czaplak 1995; Millington 1996; Shirihai tures of Arctic Redpoll, we also reproduce et al. 1996; Steele 1996). Nevertheless, the here some of the hundreds of photographs high degree of variation among redpolls and which aided the assessment of the 1995/96 the possibility of subjective interpretation of records. Although, over the last five years, a a number of characters render at least some combination of plumage features and struc- individuals extremely difficult to identify.The ture has allowed the separation of greater 1995/96 influx of redpolls into Western numbers of Arctics in the field, there remains Europe (Riddington et al. 2000) gave many the occasional individual which, on present observers a chance rigorously to test the knowledge, may not be identifiable. This identification criteria against large numbers paper is based largely on a working set of of birds in mixed flocks of Common Red- BBRC guidelines developed by AMS, KDS, polls of the nominate race flammea (known Pete Ellis and Doug Page in order to ease the as ‘Mealy Redpolls’) and Arctic Redpolls. task of record assessment. In an attempt to clarify the range of varia- In the following account, only the race 68 © British Birds 93: 68-84, February 2000 Votier et al: Arctic Redpoll identification exilipes of Arctic Redpoll is considered. which will accentuate yet further the charac- Although, in some cases, the nominate race teristic ‘pushed-in face’ and ‘steep-forehead’ could not be excluded, most (if not all) look of these already small-billed birds (plate Arctics recorded during the 1995/96 influx 44). Seen head-on, Arctics show a fatter, were of the race exilipes, and all references broader head with a fat-cheeked appearance are to that subspecies only. In addition, the and flat crown. nominate race of Common Redpoll is The feather bulk also creates the impres- referred to as Mealy Redpoll, and the race sion of a very small eye, imparting a rather cabaret as Lesser Redpoll. attractive ‘cute’ or ‘naive’ expression (plates Identifying redpolls is best achieved by 60 & 61). In side-on view,Arctics show very concentrating on a number of key features dense nape and neck-side feathering, so that which are subject to considerable individual the head merges smoothly with the body, variation. Other factors which may affect giving the hunched, bull-necked appearance appearance include actions and posture, dis- so typical of many individuals. This dense tance, light, temperature, age/sex and feathering of the nape, together with dense plumage wear: all of these need to be borne underpart feathering, lends a considerable in mind when attempting to identify any ‘depth’ to the bird, contributing to its pow- individual. While some Arctics are strikingly erful, front-heavy look. From the rear, a eye-catching (plate 41), the high degree of greater breadth is usually visible across the variation and the difficulties of keeping track nape, mantle and rump, producing a rather of individuals within often large and highly ‘lark-like’ impression when the bird is on the mobile flocks of very similar-looking birds ground (plate 41). As a result of this dense (plate 42) make for one of the thorniest plumage, Arctic Redpolls seem to have problems in birding.The main confusion risk greater difficulty in keeping their rump is with Mealy Redpoll, but Lesser Redpoll can covered, the whiteness regularly ‘peeping also present an additional identification out’ much more readily than is the case with problem. a Mealy Redpoll (plates 50, 51 & 56).Arctics The key features for identification are dis- also usually show shaggier feathering on the cussed systematically below, with reference lower belly and flanks, giving a heavy rear to photographs. Additional characters, ‘undercarriage’ and contributing to a long- including bill structure, plumage density bodied appearance (plate 41). (which will influence structure), promi- Because of their feather mass, the impres- nence of wingbars, and general size and sions given by Arctic Redpolls with sleeked- build, are more subjective and variable, but down feathers and those with fluffed-up are touched upon in the captions. feathers can be very different. On the ground, the birds look very long and solid- Structure bodied, front-heavy and neckless, with a Potentially, this is almost the most useful shaggy ‘undercarriage’ and long tail. When character of all, but probably only to feeding in birches Betula or alders Alnus, observers already familiar with both species. they may show a similar appearance, though Although structural features are subtle, they mitigated by their acrobatic behaviour, such seem to be more constant than plumage as hanging upside-down and twisting to characters, so that the majority of Arctic Red- reach seeds. When perched upright, polls show an appearance which, once however, they gradually relax their feathers, learnt, is highly distinctive. The effect is and the final effect can be almost that of a largely a result of feather density, but it mani- sphere, with hugely inflated, billowing flanks fests itself in several ways. and rump often overlapping, or even Although measurements overlap consider- obscuring, the wings (plates 44, 45, 50, 51 & ably, exilipes Arctics, because of their greater 56). feather mass, appear larger and bulkier than Bill sizes of Arctic and Common Redpolls Mealy Redpolls. This impression is height- overlap, but the ‘classic’ Arctic bill is small, ened by the paleness of their plumage. Extra short and relatively fine, with a straight or feathering around the ‘face’, particularly concave upper mandible. On some Arctics, it around the bill, can obscure the bill base, is strikingly tiny. British Birds 93: 68-84, February 2000 69 Votier et al.: Arctic Redpoll identification White rumps 45); this streaking can be so extensive as to According to Svensson (1992), a redpoll with resemble closely that on Mealy (plates 46- 10 mm or more of unstreaked white on the 48). The variation – ranging from Mealies rump will surely be an Arctic, and such birds through young Arctics to adult Arctics – is are extremely attractive (plate 43). Although subtle, but the extremes are distinctive some show only 10 mm of unstreaked white (plates 49-51). (plate 44), these are still reasonably identifi- It is important to remember that dark able; on more extreme individuals, the depth feather bases will be more obvious as birds of unstreaked white can be at least 20 mm. become more worn (particularly during late Other, apparently ‘good’ Arctics show a winter and in spring), and that these same largely white rump with small fine streaking markings are more obvious when the rump intermixed, which can be confusing (plate feathers are fluffed up. /Birdwatch Steve Young Steve 41. Arctic Redpoll Carduelis hornemanni exilipes, Langham, Norfolk, February 1996. Some exilipes are large, powerful-looking finches with strikingly pale plumage.This individual shows Arctic’s typical flat and broad head shape with steep forehead and rather bull-necked appearance.The shaggy, heavy underparts and broad, almost ‘lark-like’ structure are also typical. Robin Chittenden 42. Arctic Carduelis hornemanni exilipes and Mealy Redpolls C. flammea flammea, Cromer, Norfolk, January 1996.A flock of redpolls at Cromer contained at least four exilipes, though as many as 12 may have been present through the winter; at least two exilipes are shown here (third and fifth from right), but a number of other very pale individuals are not obviously identifiable from the photograph. Note at least one buffy Lesser Redpoll C. f. cabaret (seventh from left). 70 British Birds 93: 68-84, February 2000 Votier et al.: Arctic Redpoll identification /Birdwatch Steve Young Steve Robin Chittenden 43. Arctic Redpoll Carduelis hornemanni 44. Arctic Redpoll Carduelis hornemanni exilipes, Langham, Norfolk, March 1996. A exilipes, Langham, Norfolk, February 1996. Some ‘classic’ individual, showing extensive area (10-20 (usually young) exilipes show a rather narrow mm) of unstreaked white on rump and very pale area of unstreaked white on rump, with general plumage. Arctic has a tendency to fluff streaking from mantle invading only the upper out its rather dense plumage, which can enhance portion of rump, and a pale panel in centre of the amount of white visible on the rump. mantle. Note the rather small,‘pushed-in’ bill. George Reszeter George 45. Arctic Redpoll Carduelis hornemanni exilipes, Langham, Norfolk, February 1996. An Martin S. Scott apparently ‘classically’ pale exilipes, but, as the rump feathers are fluffed out, a lot of small dark 46. Mealy Redpoll Carduelis flammea feather bases are revealed. A number of exilipes flammea, Garlogie, Northeast Scotland, March (usually females and immatures) show grey 1996. Most Mealies show a contrastingly pale streaks across the rump and can be confused rump, which can extend to a pale panel on with Mealy Redpoll C. flammea flammea.The centre of mantle; the rump, however, is still very streaking will become more obvious as the white heavily streaked blackish. tips abrade through the winter. British Birds 93: 68-84, February 2000 71 Votier et al.: Arctic Redpoll identification Martin S. Scott P.J. Dunn 47. Unidentified first-winter female redpoll, 48. First-winter Arctic Redpoll Carduelis probably Arctic Carduelis hornemanni exilipes, hornemanni exilipes, Garlogie, Northeast Filey, North Yorkshire, 1996.
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