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Blue-headed / Cassin's Vireo in Mexico (1 Viewer)

Valéry Schollaert

Respect animals, don't eat or wear their body or s
This bird was taken in Teotitlán del Valle (Oaxaca), Mexico on 28 December 2020. I guess Cassin's Vireo, but I'd like a confirmation. Slight doubt with Blue-head because fairly bright flanks. Thanks for your help. Vireo_bf.JPG
 

KenM

Well-known member
Interesting bird! I note that there is contrast between cheek and throat (pro BHV) also the location is more Western Mexico? (pro CV) and that possible hybridisation between CV and Plumbeous Vireo might occur.....mmm?

Cheers
 

pbjosh

missing the neotropics
Switzerland
Very hard to judge some of these birds, particularly from just one static photo. The strongly colored back, the apparently cleanly separated gray/white border along the malar area, the very yellow flanks, and the (perhaps depending on how you interpret the photo) white outer tail line visible all point towards Blue-headed for me. However, these birds are challenging and with just one photo I don't think anyone would be opposed to leaving this as "Vireo sp"

I don't think that Oaxaca favors Cassin's on range - BH is traditionally mapped to winter there.
 

Valéry Schollaert

Respect animals, don't eat or wear their body or s
This is a tough one, but reviewing this article: https://www.surfbirds.com/Features/Solitary_Vireos/identification.html I favor Blue-headed Vireo for your bird.

This is a tough one, but reviewing this article: https://www.surfbirds.com/Features/Solitary_Vireos/identification.html I favor Blue-headed Vireo for your bird.
I spent 30 minutes comparing my photos and this article. The birds I see around Teotitlan, western Oaxaca has much greyer head than those of Tuxtepec, where Blue-headed V. is common. This is why I guessed Cassin's. But I understand Blue-headed is variable...
 

njlarsen

Gallery Moderator
Opus Editor
Supporter
Barbados
Any additional images, possibly showing other angles? I am leaning the same way as others but with a nagging feeling it might me wrong.

Niels
 

Valéry Schollaert

Respect animals, don't eat or wear their body or s
If I had to guess I would say Blue-headed, but without better photos it is best left Cassin's/Blue-headed Vireo.
You need a "better" photo ? I think the photo is perfect, isn't it ? I didn't find a single one better than this online. I've plenty of photos of this individual, which details you want to see to help ?
 

Valéry Schollaert

Respect animals, don't eat or wear their body or s
Someone sent me privately this message, so I keep it anonymous.

"Birds such as yours (and with multiple photos) have been a controversy for a few years here in the U.S. There are such examples where the true experts in the field come out on opposite sides with some declaring Cassin's and others Blue-headed. Some have also suggested revisiting the entire "Solitary Vireo Complex." So, you are not alone in this quandary."
 

njlarsen

Gallery Moderator
Opus Editor
Supporter
Barbados
I agree this is as good as any single image can be. However, coloration of the underside is very strong. I would like to see how the rear underside looks in an image more from below and I would like to see the rump/back in a rear view image if available.
Niels
 

Valéry Schollaert

Respect animals, don't eat or wear their body or s
I agree this is as good as any single image can be. However, coloration of the underside is very strong. I would like to see how the rear underside looks in an image more from below and I would like to see the rump/back in a rear view image if available.
Niels
Thank you Niels. Let me add a few photos.

1 : same bird as above, from back
2 : different individual in the same little flock of passerines
3 and 4 : 2 different individuals from Tuxtepec that I identified as Blue-headed Vireo, for comparison.

Interesting subject, isn't it ? I appreciate your help
 

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njlarsen

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Opus Editor
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Barbados
I have reviewed the two photos again against the photos included in above paper. I am now leaning Cassin's. Compare especially the first couple of images in the paper (the one from Vancouver Island) and the notes below. I feel the contrast between throat and side of head as well as contrast of lores in the OP images are very similar to what you see in the bird from Vancouver island and less than what you see in those labeled as true BhVi.

Niels
 

Valéry Schollaert

Respect animals, don't eat or wear their body or s
I have reviewed the two photos again against the photos included in above paper. I am now leaning Cassin's. Compare especially the first couple of images in the paper (the one from Vancouver Island) and the notes below. I feel the contrast between throat and side of head as well as contrast of lores in the OP images are very similar to what you see in the bird from Vancouver island and less than what you see in those labeled as true BhVi.

Niels
thank you for your input. I'm not sure if my bird will be "certified" as Cassin's one day, but for sure I learned a lot ; I've seen an obvious Plumbeous Vireo in the same area a few days ago, a nice field of research I guess...

Happy new year to all !
 
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia

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