David Sibley

House Sparrow – "New" for North America?

[Major updates 25 Feb 2008, adding new information about the introduced Siberian populations] You might think that the words “intriguing” and “House Sparrow sightings” are mutually exclusive, but here’s a case where they go together! In October 2007 a flock of five House Sparrows showed up in the coastal village of Shishmaref in northwest Alaska.

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Urging caution when identifying Common Redpolls

Redpoll identification is challenging because Hoary and Common Redpoll seem to show an unbroken continuum of variation from pale to dark, and there are no fully reliable differences. So birders have to rely on a subjective assessment of overall color and struggle to define the threshold for confident identification. Virtually all birders see redpolls only

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A Character Index for Redpoll identification

[edited 12 and 14 Jan, 2008, adding comments about the index] I’ve been thinking about redpolls more, and had another, more careful, look at Troy’s 1985 paper, which is filled with interesting observations and some serious “food for thought”. First of all, Troy identified redpoll specimens using a character index, which is a well-established method

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