Need ID Help from Crow Valley (Weld County)
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Joey Angstman
Sep 6, 2016, 10:55:30 PM9/6/16
to Colorado Birds
Hi,
My friend (Dan Horton) and I visited Crow Valley on Monday to see if we could find migrants that are coming through. We did in fact find some birds, but also realized we have don't know what they are. We were able to narrow it down a little bit, but definitely need some help with a couple birds. Please check out the posted pictures and let us know if we were on the right track.
What we think we had:
1) Townshend's Warbler (warbler pictures)
2) Least Flycatcher (flycatcher pictures)
3) Cassin's Vireo (vireo pictures)
We were also having a very in depth conversation on the difference between immature Townshend's Warbler vs immature Blackburnian Warblers. Can anyone offer some helpful tips for differentiating between the two (other than Townshend's being extremely more likely)?
Thanks for all the help.
Joey Angstman
Fort Collins, CO.
colorad...@aol.com
Sep 7, 2016, 11:02:35 AM9/7/16
to cob...@googlegroups.com
Joey:
Given a view of the back, Blackburnian is actually fairly easy to differentiate from similar-looking species by the white or whitish "braces" -- those streaks of contrasting pale near the sides of the back. However, your major concern with identifying Townsend's Warbler (TOWA; note the lack of an "h") is differentiating from Black-throated Green Warbler (BTNW). One of the obvious differences between TOWA and BTNW is the latter's yellow-green vent strap (a complete or not-so-complete band extending from flank through vent to flank), so nicely illustrated in your first picture. An additional concern with these two species is that they are known to hybridize, and Colorado has at least two records of such. I am a little concerned by the apparent darkness of the rear corner of your bird's auricular patch (which might suggest TOWA genes), but that could be a posture or photographic effect.
For the Empidonax, I would guess that the bird's long primary projection and relatively shortish tail suggest Hammond's, a very different look than that of Dusky (short primary projection, long tail) and a somewhat different look than that of Least (short primary projection, shortish tail).
The vireo is, indeed, a Cassin's, as suggested by the overall greenish coloration and the dull interface of throat and auriculars; Blue-headed would have a bright white throat sharply and strongly contrasting with the auriculars.
Enjoy,
Tony Leukering
currently Cut Bank, MT
Given a view of the back, Blackburnian is actually fairly easy to differentiate from similar-looking species by the white or whitish "braces" -- those streaks of contrasting pale near the sides of the back. However, your major concern with identifying Townsend's Warbler (TOWA; note the lack of an "h") is differentiating from Black-throated Green Warbler (BTNW). One of the obvious differences between TOWA and BTNW is the latter's yellow-green vent strap (a complete or not-so-complete band extending from flank through vent to flank), so nicely illustrated in your first picture. An additional concern with these two species is that they are known to hybridize, and Colorado has at least two records of such. I am a little concerned by the apparent darkness of the rear corner of your bird's auricular patch (which might suggest TOWA genes), but that could be a posture or photographic effect.
For the Empidonax, I would guess that the bird's long primary projection and relatively shortish tail suggest Hammond's, a very different look than that of Dusky (short primary projection, long tail) and a somewhat different look than that of Least (short primary projection, shortish tail).
The vireo is, indeed, a Cassin's, as suggested by the overall greenish coloration and the dull interface of throat and auriculars; Blue-headed would have a bright white throat sharply and strongly contrasting with the auriculars.
Enjoy,
Tony Leukering
currently Cut Bank, MT
Need ID Help from Crow Valley (Weld County)
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Joey Angstman <jangs...@gmail.com>: Sep 06 07:55PM -0700
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Hi, My friend (Dan Horton) and I visited Crow Valley on Monday to see if we could find migrants that are coming through. We did in fact find some birds, but also realized we have don't know what they are. We were able to narrow it down a little bit, but definitely need some help with a couple birds. Please check out the posted pictures and let us know if we were on the right track. What we think we had: 1) Townshend's Warbler (warbler pictures) 2) Least Flycatcher (flycatcher pictures) 3) Cassin's Vireo (vireo pictures) We were also having a very in depth conversation on the difference between immature Townshend's Warbler vs immature Blackburnian Warblers. Can anyone offer some helpful tips for differentiating between the two (other than Townshend's being extremely more likely)? |
Joey Angstman
Sep 7, 2016, 9:32:46 PM9/7/16
to Colorado Birds
Thank you, Tony! I was looking through my pictures again tonight and found this one. Is this the white throating you were talking about for a Blue-headed Vireo? or is still missing enough contrasting with the auriculars?
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