In each issue of BirdWatching magazine, field-guide author, photographer, and bird artist Kenn Kaufman describes how to identify birds in his long-running column “ID Tips.” Each column focuses on a few similar species and explains how you can tell them apart in the field. Kenn also includes a brief historical note or other newsworthy story about the species in each issue’s column. In our December 2017 issue, Kenn explains the identification of Snow Goose and its close relative Ross’s Goose, and he offers the story below, about the blue morph of Snow Goose, known also as the “Blue Goose.”
It’s not surprising that the “Blue Goose” was long considered a different species. This dark-bodied, white-headed morph is not randomly distributed through the Snow Goose population; it migrates through the center of the continent, and is generally uncommon east or west of that corridor. At one time, when its population was lower, it was even more tightly restricted in range.
In fact, as late as the 1920s, its nesting grounds were unknown to science. An intrepid Canadian scientist, J. Dewey Soper, spent several seasons searching remote areas of the Arctic for the birds without success. Finally, following tips from the Inuit, he visited the Bowman Bay area on the southwest coast of Baffin Island. Blue Geese were abundant there, and Soper found the first nest on June 20, 1929. A 3,000-square-mile tract of Baffin Island is now designated as the Dewey Soper Migratory Bird Sanctuary, and it’s one of the most important nesting areas for geese in Canada.
With the increase and spread of Snow Geese in general, Blue Geese also have become more widespread. But it was a shock to birders when biologists Robert and Ilse McLandress documented, in 1979, a blue morph in Ross’s Goose also. This “Blue Ross” is still exceptionally rare. Did the gene for the blue morph enter the Ross’s Goose population through interbreeding and backcrossing with Snow Geese? We still don’t know for sure. — Kenn Kaufman
Kenn Kaufman’s “ID Tips,” featuring the photographs of Brian E. Small, appears in every issue of BirdWatching. The article above is an excerpt of a column that ran in our December 2017 issue.
Read the paper about blue Ross’s Geese
McLandress, M. Robert, and Ilse McLandress. “Blue-phase Ross’ geese and other blue-phase geese in western North America.” The Auk (1979): 544-550. PDF
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