[Birdtalk] Re: Red Butte Warbler ID

[Cliff and Lisa Weisse]

The more I look at this one the more I feel it's likely a hybrid that 
includes CSWA as one parent.  Regarding whether it's a Yellow-rumped the 
pale spot on the back in photo #3 extends quite a way to the side of the 
rump, doesn't contrast much with the rest of the upperparts, and 
actually looks lime green rather than bright yellow, a better fit for 
CSWA.  Other points against YRWA include extensively pale lower mandible 
(I can't recall seeing a YRWA with a pale bill) and the shape of the 
pale throat area which in my experience with YRWA is always triangular 
and wider at the breast, not parallel edged as this bird shows.  Also 
one of the tertial edges in photo #2 looks bright yellow.  YRWA can have 
buffy tertial edges but not yellow.  Of course that's assuming the color 
is as it appears in that photo which may not be correct. 

I sent a note about this bird to a friend at the IBO research station at 
Lucky Peak (Idaho) asking what he thinks.  I'll forward his reply if he 
offers an opinion.

Cliff

Rick Fridell wrote:
> Hello Everyone,
>
> This is indeed an intriguing warbler.
>
> I think it clearly is not a Blackpoll or Bay-breasted Warbler, primarily for
> all the reasons Craig outlined. In addition, among other important missing
> characteristics a fall Blackpoll or Bay-breasted should show more distinctly
> white-tipped primaries.
>
> I agree it superficially resembles a first fall Chestnut-sided Warbler, but
> there are a couple major problems with this. First and foremost, the warbler
> shows significant (blurry) streaking on the chest, sides, and flanks
> (particularly evident in photo 4). This streaking is inconsistent with any
> Chestnut-sided Warbler plumage.  Also, a fall Chestnut-sided Warbler should
> show a marked contrast between the face and crown and a slight contrast
> between the face and white throat. This bird appears to show a strong
> contrast between the throat and the face but no evident contrast between the
> auriculars and crown. I agree the wingbars appear yellowish in a couple of
> the photos (good for Chestnut-sided), but I'm not convinced this isn't an
> artifact of the lighting in the photos.
>
> I'm a little surprised no one has brought up a first-fall Pine Warbler.
> Many characters visible in the photos (particularly photos 4,5, and 6) fit
> well for a young Pine Warbler (auricular pattern / throat contrast, breast
> smudging / streaking, bill color, tail pattern and length, etc.). However I
> think Photo 1 shows indistinct streaking on the back (although it's hard to
> tell for sure) and as hard as I try to split the eye-ring, it just looks too
> complete at the rear of eye, and unfortunately these characters should
> eliminate a Pine Warbler.
>
> So after trying to make it fit a vagrant eastern warbler, I'm actually back
> to a more obvious and probable candidate (as Matt and Cliff hinted
> towards),...... I believe it is actually a first fall Yellow-rumped Warbler.
>
> I really don't see any features on this bird that would be terribly
> inconsistent with a first fall Yellow-rumped Warbler. As Matt pointed out,
> the complete or nearly complete eye-ring is fairly common on "some drab fall
> female yellow-rumps".  In every photo the eye-ring appears to be slightly
> incomplete towards the front of the eye (appropriate for a yellow-rump). The
> auricular and throat contrast is appropriate for first-fall yellow-rumps as
> well, which often show whitish throats and chins.  Other characteristics are
> also consistent with a young Yellow-rump Warbler, including the indistinct
> streaking on the breast, sides and flanks; the back pattern (thin indistinct
> streaking, in photos 1 and 2); the prominent wingbars, tertial and primary
> edging; the overall proportions, etc. Tail length (projection past undertail
> coverts) looks a bit short for a yellow-rump, but this is hard to judge in
> the photos, and the appearance can be easily influenced by the angle of the
> photo. I would also expect a yellow-rump's bill to be darker overall, but
> young birds can show a paler area at the base of the lower mandible. Also I
> think the tail pattern shown in one of Carol's newly posted photos (#4) is a
> better fit for a Yellow-rumped Warbler and shows too much black in the tips
> of the outer retrices for a chestnut-sided. Of course all plumages of
> Yellow-rumped Warblers should show an obvious yellow rump, and I actually
> think a bit of the yellow rump may be visible in Photo 3 (lighter areas),
> although it's hard to judge with the shadows in the photos. If that's not a
> yellow rump than disregard all of the above, and I don't know what it is.
>
> A special thanks to Carol for sharing the photos and providing the extra
> images. It's always fun to puzzle over a good old fashioned "confusing fall
> warbler".
>
> Regards,
>
> Rick Fridell
> Hurricane, UT

-- 
Cliff and Lisa Weisse
Island Park, Idaho
cliffandlisa at octobersetters.com