Date: 7/30/19 9:11 pm
From: Bob Archer <rabican1...>
Subject: [obol] Re: thrush question
A good source of info in separating out all of these thrushes are the
following three papers published by Lane and Jaramillo.

I refer to them constantly.

Bob Archer

On Tue, Jul 30, 2019 at 8:28 PM <t4c1x...> wrote:

> According to Sibley's illustrations, the olive-backed form of
> Swainson's Thrush bears perhaps more resemblance to Gray-cheeked Thrush
> than it does to the russet-backed form of the same species. However, his
> illustrations show the olive-backed form as having a much broader buffy
> collar wrapping around behind the auriculars than either Gray-cheeked or
> the russet-backed form. Is this depiction accurate? If so, it seems it
> might be a useful clue in separating Gray-cheeked from the olive-backed
> form of Swainson's, should either one ever happen to show up in Oregon.
> Not that I expect to see one of either, but chance does favor the prepared
> mind.
> In terms of detecting a bona-fide Gray-cheeked, I think the chance
> would be much greater if one happened to hear one among the tens of
> thousands of Swainson's, which pass over the western Coast Range every
> fall. The flight call is distinct enough from that of Swainson's, that I
> think one could be confident of picking it out, if he heard it well. It
> certainly is something those, who listen to night-migrating Swainson's
> should be aware of.
> Darrel
> Darrel

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