[Tweeters] Cassin's Vireo vs. Purple Finch songs, Cassin's Vireo arrival

[Scott Atkinson]

Tweeters:

Good comments posted on Purple Finch alternate song likeness to Cassin's Vireo songs. Another helpful clue (not as a stand-alone however) is location of the singing bird.  Singing Purples at this time of year especially are prone to treetop perches or close by, usually in the open for maximum broadcast.  By contrast, Cassin's Vireo is prone toward mixed or coniferous forest interior, or at least interior of the tree chosen, for singing.

Dates of arrival for Cassin's Vireo are a little different than as reported by Steve.  Cassin's Vireo is long known as an April FOS bird; this cold year the migration peak may be reached after May 1st, but normally Cassin's Vireo migration is strongest in latter April in wWA lowlands.  Exceptionally, Cassin's Vireo has even arrived in the w. WA lowlands in late March, though I don't recall any such encounters in recent years.

I think 'ol Gary has explained well the reports we seem to get of very early Swainson's Thrush--that are in fact Song Sparrows (or other sp.). Seems clear enough that while a few birds have shown in the last decade of the month (especially the very last days of April), arrival  in the first week of May is the norm.

Scott Atkinson
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