This morning I was walking along, in a Pinon/Juniper hillside in western Colorado, when I heard a Vireo song. I was able to narrow it down to Plumbeous/Gray, and I decided that the notes were too fast and clear to be a Plumbeous; a Gray Vireo. No biggie, it was about the 10th Gray Vireo I had heard.
I looked up ahead of me and saw the bird singing, and it appeared very large for a Gray Vireo. I trained my binoculars on the bird, and I had a first year Cassin's Finch. At first I didn't think that the bird I was looking at was the bird singing. I kept my eye on the finch, and everytime the "Gray Vireo" would sing, the Cassin's Finch had it's bill open, pointed skyward, full of song.
I don't know much about Cassin's Finch as they're learning how to sing. Maybe they often sound like Gray Vireo, and I've just never noticed it because I've never heard that type of song come from a Cassin's in a Pinon/Juniper Habitat. Or, maybe Cassin's Finches, like some other finches, practice mimicry sometimes; if so, there were plenty of Gray Vireos they could pick up the song from.
Has anyone else heard a similar song from a Cassin's Finch, or has anyone ever heard them mimic another species?
Good day today. I also had a Northern Saw-Whet Owl calling on a point!
Love and cherish birds and all things.
Carl
Labels: fieldwork, identification, songs
3 Comments:
I am not very familiar with Cassin's Finch, but having just moved to Boise, Idaho for work for part of the summer, I have been encountering them a lot obviously. A pair started nesting above the trailer I live in. One day last week I head a vireo-like bird in the yard and I was pretty excited to search for the vireo and add a new yard bird. But the same thing happened as you described...I tracked down a singing Cassin's Finch. I've heard similar vireo-like song in a park down the road, but it also turned out to be a Cassin's Finch.
@Carl and @Anna:
There is some talk about these calls being mimicry (as you mentioned Carl) or possibly a sub-song (a few species are known to have multiple songs, or alternate songs and I believe Cassin's has at least 2 types of songs it regularly uses). It almost sounds in between a call and a song--or more musical like the song, but short and abrupt like the call, giving the impression of a vireo. In my opinion it is far closer to a call for this species than a song--but just like a vireo song. I found a rather good example on Xeno Canto
Cassin's Finch that sounds like a vireo
Think I've seen it discussed online somewhere although I can't find a link offhand, but Purple Finch can sound very close to Blue-headed Vireo as well.
This one on xeno-canto is close but they get even closer.
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