David Sibley

More vocal copying by American Goldfinch, Purple Finch, and Ovenbird

After listening carefully to Pine Siskins this year to pick out the calls of other species (see my earlier post) I have run across several other mimics. In early June in Arlington, Massachusetts I heard a remarkable American Goldfinch song that incorporated several phrases of a Song Sparrow song along with Northern Flicker and I […]

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Promising new window film may prevent bird collisions

The most recent research by Dr. Daniel Klem, who has been studying the problem of bird/window collisions since the 1990s, has just been published in the June 2009 Wilson Bulletin. It is available, along with lots of other bird/window resources, at his website here. Klem tested the effectiveness of various window treatments confirming, for example,

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Identification tips for Greenland Greater White-fronted Goose

The Greenland Greater White-fronted Goose (Anser frontalis flavirostris) is known to be a rare visitor to northeastern North America, but I have never been satisfied with a reliable, objective way of distinguishing it from the North American subspecies of Greater White-fronted Goose, also a rare visitor to the northeast. Bill color is the most frequently-mentioned

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Lesser Canada Goose in the northeastern US

The primary challenge of distinguishing Canada from Cackling Goose centers on the intermediate-sized ‘Lesser’ Canada Goose, B. c. parvipes, which reportedly nests across the boreal forest regions of western Canada and interior Alaska (more details on my website here). I’ve seen a few birds that I thought were ‘Lesser’ in the northeast over the years,

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How many rare birds did we miss before the internet?

Yesterday morning I ‘found’ Canada’s first Lucy’s Warbler… in my inbox. After reading my recent posts about rare birds, Cathy Mountain (whose redpoll photos were featured here last winter) sent me a series of pictures of a warbler that had been in her yard in Fort McMurray, northern Alberta, from November 8-10, 2008. After rejecting

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