108 Recognizable Forms

Redpolls by Ron Pittaway

Introduction (1988) treats it as representing very The American Ornithologists' long-billed individuals of nominate e. Union Check-list (1983) recognizes r [lammea. The Hoary Redpoll also two species of redpolls: Common has two subspecies in Canada: a Redpoll (earduelis flammea) and small southern race (e. h. exilipes) Hoary Redpoll (e. hornemannis. and the larger northern nominate Each species has two well-marked race (e. h. hornemannii. subspecies in Canada (Godfrey 1986). Troy's (1985) widely read and However, the taxonomy of redpolls much quoted study concluded that has been much debated. Some the southern race of the Common authors suggest lumping all redpolls Redpoll (e. [. flammea) and the into a single species, while others southern race of the Hoary Redpoll propose splitting them into four (e. h. exilipes) should be lumped as separate species. Regardless of how one highly variable species. His many species there are, classic assumption was that intermediate individuals of each of the four forms birds represented hybrids. This view are recognizable in the field. The appealed to many ornithologists, legendary George North of Hamilton birders and banders who had found actually saw the four forms of themselves perplexed by redpoll redpolls in one flock at Aldershot on identification. However, later 23 March 1958 (North 1983)! In order researchers questioned Troy's to recognize these forms, we require taxonomic conclusions. Seutin et al. a sound knowledge of the field (1989) noted that Troy failed "to take marks, plus a thorough understanding age dimorphism into consideration in of redpoll plumages, effects of wear, his analysis". In fact, Knox (1988) age classes and molts. It is a could find no direct evidence of fascinating identification challenge, hybridization anywhere in the large worthy of our consideration. area of overlap between Common and Hoary Redpoll populations, Taxonomy although he suspected that occasional The Common Redpoll has two hybridization does occur. Based on subspecies in Canada: the smaller biochemical evidence and southern nominate race (e. [. (electrophoresis). Marten and Johnson flammeai and a larger northern race (1986) found that the two most (e. t. rostrata). A third race, e. t. similar forms of Common Redpoll (e. holboelli, is considered by most r [lammeai and Hoary Redpoll (e. h. authorities to be of doubtful validity exilipes) "seem to have split 550,000 (AOU 1957, Godfrey 1986). Knox

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Figure 1: Adult male Common Redpoll. Drawing by Chris Kerrigan. years ago". These two forms "are the two large northern redpolls (c. h. clearly near the boundary of species homemannii and C. f. rostrata) also formation" (Knox 1988). Both Knox occur together over a wide area with (1988) and Herremans (1989) virtually no evidence of considered the two forms to be a pair interbreeding. Previously, Todd of sibling species. Sibling species are (1963) and recently Herremans (1989) two or more closely related species have proposed four species of that have very similar morphology. redpolls: C. hornemanni, C. exilipes, C. The Empidonax flycatchers are a good rostrata and C. f/ammea. See Figure 2. example of sibling species. Similarly,

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Plumages, Molts and Ageing A large flock of "Southern " A knowledge of redpoll plumages Common Redpolls (c. f. flammeai will will help in understanding the show four plumage types: adult variation seen in redpoll flocks. males, adult females, first year males, Instead of resulting from and first year females. Add another hybridization, much of the confusion form to the above flock and now over intermediate birds can be there are eight possible plumage explained by age and sex differences, types! and individual variation (Knox 1988). The following is only a general "Southern" Common Redpoll outline of the plumages, molts and {e. f. {lammeaJ ages in redpolls. This low Arctic form breeds Adult (definitive basic) redpolls south to northern Ontario (James undergo a complete molt (all feathers) 1991). It is an erratic winter visitor to once a year after the breeding season. southern Ontario, sometimes in large Because of buffy or greyish feather numbers. This is the commonest edges which gradually wear off, form in the province, far adults in fresh (new) fall plumage are outnumbering the other three forms much paler than the same birds in and is the standard by which the worn (old) breeding plumage. In other forms are compared and males, the pink coloration is also pale recognized. Study the flocks (bird when fresh, gradually becoming feeders are ideal) and learn the richer and redder by spring. Feather different plumage variations. Adult wear allows redpolls to don a males are richly coloured with rosy breeding dress without the need to pink while first year males are molt (Newton 1972). This change is somewhat darker and often washed well illustrated in the National with light pink. Adult females on the Geographic Society's Field Guide other hand usually lack any pink (Scott 1987). Compare the colouration (sometimes tinged) and illustrations of the Common Redpolls first year females are the darkest and labelled winter and breeding on page most heavily streaked of the age 439. classes, at times almost siskin-like. Juveniles lack the red cap and In all plumages, this form is black chin of the adult birds. On the usually noticeably streaked on the breeding grounds in late summer, sides, rump and undertail coverts. juveniles undergo a partial (body) The bill is longer and less stubby molt to first year (first basic) than the Hoary'S. Individuals plumage retaining most of the showing characteristics that are juvenile wing and tail feathers. intermediate between C. f. f/ammea Seasonally compared, first year birds and C. h. exilipes are best left are darker and more streaked than unidentified. their respective adults. Redpolls wear their first year plumage for "Greater" Common Redpoll approximately one year, after which {e. f. rostrata] they molt completely into adult or This large and dark form breeds definitive basic plumage. on Baffin Island and Greenland (Todd

ONTARIO BIRDS DECEMBER 1992 c. f flammea C. h. exilipes

C§ e- sc: t'l o z c. f rostrata C. h. hornemanni sc: cc t'l •.... Figure 2: Common Redpolls [left] and Hoary Redpolls [right}, Drawing by Michel Gosselin. •.... "w •.... 112

1963). In parallel with the two Cadman et al. 1987) reported that it subspecies of the Hoary Redpoll, "may breed in low numbers on the there is also a gap between the tundra of Hudson Bay" in Ontario. breeding ranges of the two subspecies During redpoll flight years, it is of the Common Redpoll. See the usually possible to find a few range map in Godfrey (1986). It is a "classic" adult males. They stand out winter visitor "in small numbers to by their very white "frosted" southern parts of the East from appearance, pure white rumps, paler Ontario to Newfoundland" (Godfrey and less extensive pink suffusion on 1986). Richard Poulin [pers. comm.] the breast, lightly streaked flanks, has banded hundreds of redpolls near and very lightly streaked to Ottawa, and reports that "Greaters" immaculate undertail coverts. are more common than Hoary "Southern" Hoaries are similar in Redpolls during some winters. Look size to "Southern" Commons, but for this distinctive subspecies during usually have shorter, more obtuse redpoll flight years. (stubby) bills imparting a distinctive The "Greater" is somewhat larger "pushed in face" appearance. Many (averaging 14.0 cm) than the first year and some adult female "Southern" race which averages 12.5 "Southern" Hoaries can be quite cm in length (Newton 1972). The streaked on the rump and sides (Knox difference between the two races of 1988). These "intermediate birds" are the Common Redpoll is "fairly probably best treated as unidentified. obvious when the two birds are The reader is referred to the excellent together in the same flock" [Peterson article by Lansdown et al. (1991) on 1947). "Greater" field marks include the identification of this form. "larger size with thicker bill, coloration somewhat darker and browner than in flammea, adult males "Hornemann's" Hoary Redpoll with red of under parts less extensive {C. h. hornemanni] and less intense" (Godfrey 1986). The "Hornemann's" or Observers familiar with "Greaters" "Greenland" Hoary Redpoll is the in the field have described them as largest and palest of the redpolls somewhat House Finch-like because (Godfrey 1986). There is apparently a of their stout bills, heavy builds and gap between the breeding range of general darker colouration with the two subspecies of the Hoary conspicuous streaking on the Redpoll [Todd 1963). This race breeds underparts. in the Canadian high Arctic and Greenland and "is a great rarity "Southern" Hoary Redpoll south of the tundra at any season" {C. h. exilipes] (Aubry et al. 1987). The American This form breeds in the low Ornithologists' Union Check-list Arctic, and much of its range (1957) lists a record from Galt overlaps that of the "Southern" (Cambridge), Ontario. The specimen Common Redpoll. It breeds regularly is now in the Royal Ontario Museum south to Churchill, Manitoba (Jehl (North 1983). (See North's account of and Smith 1970), and Middleton (in this specimen and his observation of

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the four forms of redpolls in the worth quoting here, as an example of Postscript to this article. 1 his interest in recognizable forms: "Hornemanns" Hoary Redpoll is "The McIlwraith Loan Collection a larger bird (averaging 14.0 cm] than of birds used to be housed in the the "Southern" Hoary which Hamilton Museum on the second averages 12.5 cm in length (Newton floor of the old Public Library and 19721.Todd (19631states that there is Art Gallery which stood on the east "no overlap in measurements" side of Centenary Methodist Church. between the two subspecies. Back in the 1920's I used to visit the Compared to the "Southern" Hoary museum often to admire the birds Redpoll, "Hornernann's" is known by and study them carefully. Among the its larger size, overall whiter most striking was the big white appearance, less prominent streaking Greenland Redpoll, that seemed to be on the sides and flanks, and as big as a Snow Bunting. It was immaculate undertail coverts; males collected about 1863 by a friend of have less pink which is of a different Mr. McIlwraith's from a small flock hue, some showing a mere trace of in the town of Galt. pink suffusion on the breast (Todd For many years I searched the big 19631.Females and first year birds or small flocks of redpolls that visited are probably recognizable, if directly us almost every winter, but without compared to the other forms success in finding this big and hoary (especially the two smaller ones], by bird. Then on March 23, 1958, on their pale colouration and larger size. one of our weekly birding trips Richard Poulin (pers. comm.] has together, Dr. R.G.C. MacLaren and I observed this form in the high Arctic. visited a spot that had produced good He describes it as being "really birds in previous springs. This was an distinctive; a big, very white redpoll extensively open field off the Plains suggesting a Snow Bunting"! Road at Aldershot that was part of the property of Mrs. Towsend's at Summary Oaklands. On walking over the field Common and Hoary Redpolls we came on a flock of redpolls appear to be valid species. The feeding on weed seeds. To our delight "intermediate birds" reported there was a big white redpoll, twice between C. f flammea and C. h. as big as the Common Redpolls, the exilipes are apparently the result of Greenland Redpoll that I had been age, sex and individual variation and searching for for thirty years. But this not interbreeding. Some authorities was not the only rare bird there. On recognize four species of redpolls. looking over the flock we found one Not all redpolls will be identifiable to specimen of the commoner small species or subspecies, but "classic" white-rumped Hoary Redpoll and one individuals of each form are very individual of the Greater Redpoll. recognizable. This latter is classified as a subspecies of the Common Redpoll, but it is a Postscript much larger bird, more the size of a George North's (19831description Purple Finch and has a much heavier of his experience with redpolls is bill, more like a grosbeak's. I have

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seldom seen the Greater Redpoll Godirey, W.E. 1986. The Birds of Canada. since the winter of 1929-30 when I Second Edition. National Museum of Canada, found them on the north shore of the Ottawa. Dundas Marsh." Herremans, M. 1989. Taxonomy and evolution in redpolls. Ardea 78: 441-458. Acknowledgements [ames, R.D. 1991. Annotated Checklist of the Birds of Ontario. Second Edition. Life I thank Bill Crins, Bob Curry, Sciences Miscellaneous Publications, Bruce DiLabio, Michel Gosselin, Royal Ontario Museum, Toronto. Brian Henshaw, Henri Ouellet, jehl, j.j. and B.A. Smith. 1970. Birds of the Richard Poulin, Ron Tozer and Mike Churchill Region, Manitoba. Special Public- Turner. I wish to especially thank ation Number 1, Manitoba Museum of Man Ron Tozer for his critical review of and Nature, Winnipeg. the manuscript and assistance with Knox, A.G. 1988. The taxonomy of redpolls. the literature search. I also thank Ardea 76: 1-26. Mike Turner for his critical review of Lansdown, P., N. Riddiford and A. Knox, 1991. Identification of Arctic Redpoll Carduelis the manuscript and for logistical hornemanni exilipes. British Birds 84: 41-56. support. Michel Gosselin supplied me Marten, j.A. and N.K. [ohnson. 1986. Genetic with much valuable information as relationships of North American Cardueline well as kindly allowing me to use his finches. Condor 88: 409-420. superb illustrations which previously Newton, I. 1972. Finches. Collins, London. had been published (in part] in North, G. W. 1983. Greenland Redpoll. American Birds. I thank Christine The Wood Duck 36: 119. Kerrigan for her fine sketch of the Peterson, R. T. 1947. A Field Guide to the Birds. male Common Redpoll. Houghton Mifflin Company, Boston. Scott, S.L. [ed.]. 1987. Field Guide to the Birds Literature cited of North America. National Geographic Society, Washington, D.C. American Ornithologist's Union. 1957. Check-list of North American Birds, 5th Seutin, G., P. T. Boag and L.M. Ratcliffe. edition. American Ornithologist's Union, 1989. Plumage variability in North American Washington, D.C. redpolls [Aves: Carduelinae): the importance of sexual and age dimorphisms. The Musk-ox A•••erican Ornithologist's Union. 1983. 37: 116-121. Check-list of North American Birds, 6th Todd, W.E. C. 1963. Birds of the Labrador edition. Alien Press Inc., Kansas. Peninsula and Adjacent Areas. Carnegie Aubry, Y., M. Gosse/in, and R. Yank. 1987. Museum and University of Toronto Press. The fall season, Quebec region. American Troy, D.M. 1985. A phenetic analysis of the Birds 41: 406. redpolls Carduelis flammea [lammea and Cadman, M.D., P.F.]. Eagles, F.M. Helleiner C. hornemanni exilipes. Auk 102: 82-96. {compilers}. 1987. Atlas of the Breeding Birds of Ontario. University of Waterloo Press, Waterloo, Ontario.

Ron Pittaway, Box 619, Minden, Ontario KOM2KO