Email sent in by Ryan O'Donnell:

I solicited expert opinions via the ID Frontiers group. The consensus was unanimous in favor of Tropical Kingbird over Couch's. Here are the responses I received, some privately and some publicly. In short, all five experts who responded felt confident this was a Tropical Kingbird.

-Ryan
 

Michael L. P. Retter (Guide with Tropical Birding):

That's a honker of a bill. I can't believe it's a Couch's.
 

Forrest Rowland (Guide with Rockjumper Worldwide Birding Adventures; Nikon Birding Prostaff):

Ryan,

I see hundreds of Tropicals in a year, not too many Couch's...but if this is a Couch's...than I'm a monkey's uncle. Sorry to put it so plainly, as there are many gray areas in the ID. Bill length at the extreme is not one of them, in my experience. The length and shape of this individual's bill puts it squarely, and unequivocally, in Tropical Kingbird territory.

If there is much dissention on this topic, please reply. But I highly doubt anyone will disagree that this is a Tropical Kingbird. I just looked at the first photo, and didn't feel the need to go any further.

My two cents worth....

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Ryan,

I suppose I may have been dismissive, but I am curious as to what the concensus says on this, as it something I dealt with in Delaware a few years ago. That bird was a Tropical Kingbird, as well, but the bill was much less massive than the individual in the photo you've posted. I suppose I am most curious because I see the discussion getting quite technical, into moult details, and I'm wondering if that's entirely necessary.

Has Alvaro chimed in on this, yet? We were all just hanging out in the RGV recently, and this topic came up, though briefly.

I looked at the rest of the photos, and am unmoved in my opinion, based entirely on the head features, thus far. Contrast between lores/cheek/ear coverts and throat looks good for Tropical...but it is so hard for me to get past the massive, long, bill of this bird. I can't fathom a Couch's with those bill dimensions. Also...though I might be mistaken, I believe the tertials covering the secondaries are a feature more consistent with Tropical, but like the others said....you might hope to hear back from Pyle.

Cheers,

Forrest
 

Kevin Karlson (Author of The Shorebird Guide, writes "Birder's ID" column in Wild Bird magazine).

Ryan and all;
I have just returned from the Rio Grande Valley in Texas where I carefully studied over 20 different Tropical Kingbirds to reinforce my field ID conclusions of these two species (Couch's and Tropical) with regards to their bill, head and tail shape differences. It seems that the extreme large-billed Tropicals (either males or females, I am not sure which sex has the larger bills and diagnostic head shape) that show very long bills that are flatter from top to bottom and longer than any Couch's are fairly easy to identify due to their very long, flat bills and their deeper head profile with a shallow forecrown and flatter head compared to Couch's shorter, thicker bill and noticeably steeper forecrown with a rounded or domed head shape. This bird from Utah falls into the extreme Tropical range in my opinion, and I would not hesitate to call this a Tropical Kingbird in the Rio Grande Valley even if it did not call.

Extreme Couch's that don't resemble Tropical Kingbird in head/bill/tail shape have very short, thick bills and less deep heads from front to back and very rounded crowns in relaxed birds, and a mostly squared-off tail tip. Problems occur with shorter-billed Tropicals (males or females?) that show less deep head profiles from front to back, and bills that don't exhibit the extremely long, flat bills. I photographed a group of about 12 Tropicals two days ago that contained some obvious head/bill shapes of Tropicals, and some that were very troublesome due to comparable bill and head shapes with overlapping Couch's features. All of these birds were calling, so there was no problem putting a concrete ID to all of them. I will post a few photos of these birds, including obvious versus overlapping birds tomorrow after I have time to decompress from my return trip late last night. Overlapping Couch's/Tropicals have very similar intermediate bills with regards to thickness and length, similar forked tails, and head shapes that appear to me at this point to be very similar.

I have a photo of an extreme short/thick-billed/rounded crown Couch's on my website: , and a long, flat-billed, shallow-forecrowned, deep-headed Tropical as well: , but the recent photos of troublesome Tropicals from Texas two days ago are more interesting since the ID of silent birds would be impossible to me at this point. I don't think that there is any question as to the ID of the Utah bird based on its bill length/shape and head shape with very shallow forecrown. I have observed numerous calling Couch's over the last several years to become more familiar with their structural features range, and none of them exhibited the extreme bill length and shape and head shape of the Utah bird.

As for the bird responding to the tape call, I am not sure that this is helpful if it did not call back. I recently identified a silent yellow kingbird in Corpus Christie in mid-September as a Couch's that had a distinctly forked tail but a fairly thick, shortish bill. Since Tropical is a resident in this area now, David Sarkosi of Houston played the Tropical call to the bird. It seemed agitated at first, but then gave a perfect Couch's call. I think either species might be agitated by either call at first.
 

Peter Pyle (author of Identification Guide to North American Birds):
Traylor's original work on wing morphology in Tropical and Couch's kingbirds was based on adults, something I neglected to make clear in the identification guide, though updated shortly after publication in the errata: http://www.birdpop.org/Downloa...

To make matters worse, the symbols for Figure 166 (p. 253) are reversed, though the illustration shows it correctly.

There is some evidence that morphology in first-fall birds with juvenal primaries (HYs) may not be as diagnostic although I suspect that the morphology differences, in particular p10 usually < p5 in Tropical and p10 usually > p5 in Couch's, should still be at least an average character to consider in HYs.

I believe that the Utah bird is an HY based on the shape of the outer primaries and rectrices. It seems to have replaced most of the lesser and median coverts but no other wings feathers yet. This would be the conclusion looking at the images taken by Erik Huish but a case could be made for an adult female based on the open-wing image taken by Jeff Cooper, as based on a possible notch to the outer primary and rectrix shape and pattern. In either case, and based on this last image, it looks like p10 does fall short of p5, supporting Tropical. Assessing this on images can be hard, and account for how open the wing is must be made.

Otherwise I also agree with Kevin Karlson that bill size and shape appears much better for Tropical and all-in-all I support this identification. There seems to be quite a few of these in the western US this fall and, so far, all have looked like or been confirmed as Tropicals, so it appears a good year for them.

Peter
 

Kevin McGowan (Instructor, Cornell Laboratory of Ornithology):

I agree with Peter that p5 appears longer than p10, indicating Tropical. It's hard to judge on an open wing. For comparison, I have some wing formula photos on an old web page at http://www.birds.cornell.edu/c...

Kevin

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