Red-tailed Hawk subspecies abieticola
Red-tailed Hawk subspecies borealis
Map from The Red-tailed Hawk Project
I did the Hawk Migration Association's Winter Raptor Survey yesterday in MA in cold, completely cloudy skies with about 7 In. snow cover. The Red-tailed Hawks were not soaring, but hunted by perching. Look at the fascinating difference in these two Red-tailed Hawks I saw. The colorful one on the left, with a dark throat, buffy wash aross the chest, and much heavier, blobby belly band might possibly be a candidate for the abieticola subspecies (Buteo jamaicensis abieticola). There has been confusion and disagreement about this subspecies with much to learn. W.E. Clyde Todd was the first to describe it in 1950, naming it abieticola "dweller of the firs" since Abies is the genus of true firs and he thought its breeding range was in the Balsam Fir range. Its breeding range is in the boreal zone from Alaska to Atlantic Canada. How cool is that to think this northern visitor has come to spend the winter here. The paler bird on the right looks like our local borealis subspecies who breeds from sw. Alberta east to Maritime Provinces on the southern periphery of the Boreal Forest, and south from cen. Texas east to n. Florida, winters from n. Great Plains, the Great Lakes region and s. New England south to e. Mexico. Red-tailed Hawk subspecies are complicated there are 16 subspecies (according to Birds of the World) in two groups with much regional variation.
The wintering range of abieticola is in the U.S. east of the Rocky Mountains and there is much to learn about the wintering and migration habits of this subspecies. You can help by paying more attention to the redtails you see and uploading your photos to eBird. To learn more about this subspecies see this excellent paper by Jerry Liguori and Brian Sullivan. There is also ongoing research on this and other subspecies of redtails by The Red-tailed Hawk Project who consider abieticola to be ploymorphic.
There is also ongoing research on this and other subspecies of redtails by The Red-tailed Hawk Project who consider abieticola to be ploymorphic, see here.
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