Ontbirders,
After seeing the hybrid Common x Barrow's Goldeneye recently in Ottawa, I
did some research on hybrid goldeneyes and hope you find this of interest.
Hybrid Common x Barrow's Goldeneyes are more frequent than most birders
realize. The large Sibley (2000) is the only guide to illustrate an example
of this hybrid. Martin and Di Labio (1994) cautioned that goldeneye hybrids
are being misidentified as Barrow's. Record Committees reviewing
extralimital Barrow's in some cases may want photo documentation to exclude
the possibility of first generation hybrids and backcrosses. This post
deals only with males in definitive alternate (adult breeding) plumage.
1. Hybrid misidentified as a Barrow's
Goldeneye. http://www.spflrc.org/~walker/photodetail.php?id=10510
2. Comparison of hybrid and
Barrow's. http://www.birdphotography.com/species/bago.html
3. Seven photos of hybrid and a Barrow's Goldeneye with Common Goldeneyes
on OFO website. http://www.ofo.ca/photos/goldeneyehybrid/ I saw this
hybrid. It displayed like a Barrow's and had a greenish head sheen similar
to the nearby Common Goldeneyes.
4. Probable hybrid. http://www.suttoncenter.org/okbirdspix24.html This
bird may be the offspring of a first generation hybrid backcrossed with a
Barrow's.
5. Probable hybrid. http://www.peninsulasportsman.com/images/BGE1.jpg
These birds may be offspring of a first generation hybrid backcrossed with
a Common. Note black edges on scapulars are wider than in Common Goldeneye.
6. Hybrid. http://www.notason.com/oiseaux/id362.htm Would this bird be
identified as a Barrow's without a photo?
7. Photo of hybrid and Barrow's and a short note in the Wilson
Bulletin. http://elibrary.unm.edu/sora/Wilson/v088n02/p0348-p0349.pdf
8. Finally, I've often wondered about the photo of a male Barrow's in the
February 1986 issue of Birding, vol. 18, no. 1, p. 18 (Tobish 1986). This
photo was taken at the Washington Zoo by Claudia Wilds (fide Bruce Di
Labio) of probable birds of Icelandic origin. Photos can be misleading, but
this male looks odd to me having seen hundreds of Barrow's in North
America. It may be an Icelandic Barrow's as Palmer (1976) says in adult
males "there are differences (hard to describe) in contour of head between
birds of Iceland, e. N. Am., and w. N. Am." However, I wonder if it's a
backcross that is mostly Barrow's for the following reasons: (1) greenish
head sheen suggests Common Goldeneye ancestry; (2) head shape is somewhat
like a Barrow's, but not quite typical of that species; (3) white facial
crescent is intermediate in shape and barely extents above top of bill; (4)
the facial crescent on typical Barrow's is more pointed at top and usually
reaches well above top of bill and eyes; (5) the white spots on the
scapulars are larger than typical Barrow's and the three forward spots form
one large spot, usually separated by black on Barrow's; (6) width of
diagonal black line dividing white wing coverts is narrower than on most
Barrow's; and (7) black spur on side of breast is smaller than on most
Barrow's. I conclude that these 7 points cast doubt about this bird being a
pure Barrow's.
Note: Statements about these hybrids are "educated guesses". None are
proven by independent evidence such as known parents and genetics.
Acknowledgements: I thank Michel Gosselin of the Canadian Museum of Nature
for discussions and web links to hybrid goldeneyes. Thanks to Bruce Di
Labio, Chris Escott and Bruce Mactavish for sending me photos of hybrid
goldeneyes from Ontario, British Columbia and Newfoundland.
References: (A) Martin, Paul R. and Bruce M. Di Labio. 1994. Identification
of Common x Barrow's Goldeneye Hybrids in the Field. Birding 26(2):104-105.
(B) Palmer, Ralph S. (editor). 1976. Volume 3, Waterfowl. Handbook of North
American Birds. Yale University Press. (C) Sibley, David Allen. 2000. The
Sibley Guide to Birds. Alfred A. Knopf, New York. (D) Tobish, Thede. 1986.
Separation of Barrow's and Common Goldeneyes in All Plumages. Birding
18(1):17-27.
Ron Pittaway
Ontario Field Ornithologists
Minden and Toronto ON
E-mail: [EMAIL PROTECTED]
