[Ontbirds]Redpoll Challenge - 4 subspecies

[Jean Iron]

The Redpoll Challenge: This is a major redpoll winter in southern 
Canada and the United States. The legendary George North of Hamilton, 
Ontario, once saw all four North American redpoll subspecies in the 
same flock on 23 March 1958 near Hamilton (North 1983, Curry 2006). 
Fifty years later this could be the winter to do it again. On 15 
December 2007, Ron and Doug Tozer found a big "snowball" Hornemann's" 
Hoary Redpoll (nominate hornemanni) on the Minden Christmas Bird 
Count. This is the rarest redpoll in southern Canada. On 14 December 
2007, I saw two "Greater" Common Redpolls (rostrata) at our feeders 
in Toronto and there have been several other recent reports. With 
these two High Arctic subspecies and probably record numbers of 
"Southern" Hoary Redpolls (exilipes) in flocks of "Southern" Common 
Redpoll (nominate flammea), we have all four North American 
subspecies in southern Ontario this winter. Below I summarize the 
basic information needed to understand and identify redpolls with 
links to photos.

Taxonomy: The American Ornithologists' Union (1998) recognizes two 
species: Common Redpoll (Carduelis flammea) and Hoary Redpoll (C. 
hornemanni). Each has two subspecies (races) breeding in North 
America. Discussion about lumping or splitting redpolls has been off 
the "radar screen" in recent years. The four subspecies are described below.

1. "Southern" Common Redpoll (nominate flammea): This is the 
commonest of the four subspecies in southern Ontario. It is the 
standard to which the other three are compared. In most plumages, it 
is noticeably streaked on the sides, undertail coverts and rump. 
However, adult males in winter have more contrasting whiter rumps 
(fewer streaks and often pinkish) than on worn breeding birds. Adult 
males are pink-breasted. First year males are somewhat darker and 
often washed with light pink. Adult females usually lack pink 
(sometimes tinged) and first year females are the darkest and most 
heavily streaked of the four age/sex classes.

2. "Greater" Common Redpoll (rostrata): This large and dark 
subspecies breeds on Baffin Island and Greenland. Greater Redpolls 
are a winter visitor in small numbers to the southern parts of 
eastern Canada from Ontario to Newfoundland (Godfrey 1986) and to the 
northeastern United States. Greaters are more frequent than Hoarys in 
some winters (Pittaway 1992). The Greater is larger (averages 14.0 cm 
compared to 12.5 cm for flammea) and heavier. Other field marks are 
the Greater's thicker bill and somewhat darker and browner coloration 
with conspicuous heavy streaking on the underparts usually extending 
to the undertail coverts. Adult male Greaters have "red of underparts 
less extensive and less intense" than flammea (Godfrey 1986). Males 
lack red on the malar area, which flammea males usually have (Beadle 
and Rising 2006). Some observers describe Greaters as House 
Finch-like. See the excellent identification article on Greater 
Redpoll by Beadle and Henshaw (1996) in Birders Journal 5(1):44-47, 
illustrated by Beadle. The differences between the two Common Redpoll 
subspecies are usually obvious when the two are together for 
comparison (Peterson 1947).

3. "Southern" Hoary Redpoll (exilipes): This subspecies breeds in the 
Low Arctic and much of its range overlaps that of the "Southern" 
Common Redpoll (flammea). It is the much commoner Hoary subspecies, 
and is similar in size to the flammea Common Redpoll. During redpoll 
flight years, it is usually possible to find a few classic adult male 
exilipes Hoarys. Compared to the "Southern" Common Redpoll, they are 
more frosted with white rumps, have lightly streaked flanks and very 
lightly streaked to pure white undertail coverts. Adult females and 
especially first year females can be noticeably streaked. Exilipes 
Hoary is similar in size to flammea Common, but may look slightly 
larger because of its whiter plumage. Hoarys have shorter, more 
obtuse (stubby) bills imparting a distinctive "pushed in face" 
appearance. Many females are identifiable by overall paler coloration 
and bill shape. Individuals appearing intermediate between exilipes 
and flammea are best left unidentified.

4. "Hornemann's" Hoary Redpoll (nominate hornemanni): This is the 
largest, palest and rarest redpoll. Hornemann's breeds in the 
Canadian High Arctic Islands and Greenland and is a great rarity in 
southern Ontario and Quebec. Hornemann's is larger (averages 14.0 cm) 
than "Southern" Hoary (exilipes) which averages 12.5 cm. It is whiter 
with less streaking on the sides and flanks and has immaculate white 
undertail coverts. Adult males have less pink than exilipes, some 
showing only a trace of pink suffusion on the breast. Females and 
first year birds are recognizable if compared directly to the two 
small subspecies, flammea and exilipes, by their larger size. See the 
excellent article on redpoll identification by Czaplak (1995) in 
Birding 27(6):446-457. His photo of Hornemann's on page 448 is 
correctly identified in my opinion. Note larger size of the 
Hornemann's in the photo in American Birds 42(2):239, which is 
reproduced on Jean's website link below. See also Doug Tozer's photo 
and Ron Tozer's detailed description of the recent Ontario 
"Hornemann's" on Jean Iron's website link below. See David Sibley's 
website link below.

A. Why is there so much plumage variation in redpolls?  A flock of 
one subspecies of the Common Redpoll (flammea) will show four plumage 
types: adult males, adult females, first year males and first year 
females. Since there are four redpoll subspecies, a large flock 
potentially could have 16 plumage types, plus considerable individual 
variation.

B. What is the Greenland Redpoll? Historically, the name Greenland 
has NOT been used in North America to describe the rostrata "Greater" 
Common Redpoll (Peterson 1947, Todd 1963, Bent 1968, Terres 1991, 
etc.). However, Greenland Redpoll is the European name for "Greater" 
Common Redpoll (Newton 1972, Jonsson 1993, etc.). Most North American 
publications use Greenland Redpoll for "Hornemann's" Hoary Redpoll 
(Nash 1905, Macoun and Macoun 1909, Taverner 1953, North 1983, etc.). 
The name Greenland causes confusion. Most of our Hornemann's Hoary 
Redpolls and Greater Common Redpolls are coming from Canada, not 
Greenland. To avoid confusion, it is preferable to include the 
subspecies scientific name after the common name, particularly when 
first mentioned: (flammea), (rostrata), (hornemanni) and (exilipes).

TAKE THE REDPOLL CHALLENGE: This is the first winter in decades to 
match George North's Ontario record of four redpoll subspecies in one 
day. Even more amazing, all four were in the same flock. I am not 
aware that North's record has been matched in southern Canada or the 
northern United States. However, Roland C. Clement saw all four 
subspecies on 12 March 1944 at Indian House Lake in northern Quebec 
(Lat 56 15' 0 N, Long 64 42' 0 W) south of Ungava Bay close to 
Labrador. Clement in Todd (1963) reported "a feeding flock of mixed 
migrants that contained ten rostrata, thirty flammea, two hornemanni, 
and about six exilipes."

Three websites with redpoll information and photos.
Jean Iron <http://www.jeaniron.ca/2007/Redpolls/index.htm>
Tommy Thompson Park Bird Research Station in Toronto <http://www.ttpbrs.ca/>
David Sibley <http://sibleyguides.blogspot.com/> Scroll down to 
Tuesday December 4.

Acknowledgements: I thank Michel Gosselin of the Canadian Museum of 
Nature for information on redpoll taxonomy and identification. Doug 
Tozer kindly provided his photo of the recent Minden "Hornemann's" 
Redpoll. Jean Iron and Ron Tozer made many helpful suggestions.

Literature Cited: I can supply full references.

Ron Pittaway
Minden and Toronto ON