Re: Willow Flycatcher?

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Posted by John Boyd on 07:13:43 09/13/04

In Reply to: Willow Flycatcher? posted by Rock Jetty

I'm glad you brought this up.

Eastern Willows and Alders are impossible to separate visually. This is doubly true in the fall when plumage is worn. It's also much harder to separate them from the other flycatchers in worn plumage (Least, even Yellow-bellied) than is generally realized as any distinguishing characteristics can be worn away (e.g., the eyering can be completely worn away on a fall Least). This is why we emphasize vocalizations for solid ID's and it is why banders use the term "Traill's". Personally, I don't find the written descriptions of the calls useful and recommend listening to them on tape.

This bird gave a Willow call, therefore it is a Willow.

In terms of structure, on average Least has short primary projection, Traill's (Alder or Willow) and Yellow-bellied moderate primary projection, and Acadian long primary projection. The phrase "on average" hides many sins. The ranges overlap and only extreme birds can be separated by primary projection alone, even in the hand.

Pyle, "Identification Guide to North American Birds" (p. 219) gives the following ranges (95% confidence interval) for longest primary - longest secondary: Least, 9.0-15.7. Traill's, 10.2-17.4. Yellow-bellied, 10.3-17.5. Acadian, 13.3-23.5.

So if you see an eastern empid with a 15mm primary projection, it could be any of them!

: Hello all,
: I recall seeing a probable Willow Flycatcher in the same area at Barnes last year on Sept. 26 (recall posting 9/27/03). The bird was seen by Brian Rapoza, myself, and a couple of my friends. Even so it's identity was never 100% confirmed, although all field marks led to Willow (particularly comparing distances from base of bill to tip and to eye and also noticing short primary projections) as Brian pointed out. Hey is it me, or does the bird John photographed have longer primary projections than a Willow should have? Hey these ain't fighting words, just an observation. By the way, that is a nice photo John, what's your opinion on the primaries?
:
: Cheers,
: from Arkansas,
: The Rock

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Comments:	: I'm glad you brought this up. : : Eastern Willows and Alders are impossible to separate visually. This is doubly true in the fall when plumage is worn. It's also much harder to separate them from the other flycatchers in worn plumage (Least, even Yellow-bellied) than is generally realized as any distinguishing characteristics can be worn away (e.g., the eyering can be completely worn away on a fall Least). This is why we emphasize vocalizations for solid ID's and it is why banders use the term "Traill's". Personally, I don't find the written descriptions of the calls useful and recommend listening to them on tape. : : This bird gave a Willow call, therefore it is a Willow. : : In terms of structure, on average Least has short primary projection, Traill's (Alder or Willow) and Yellow-bellied moderate primary projection, and Acadian long primary projection. The phrase "on average" hides many sins. The ranges overlap and only extreme birds can be separated by primary projection alone, even in the hand. : : Pyle, "Identification Guide to North American Birds" (p. 219) gives the following ranges (95% confidence interval) for longest primary - longest secondary: Least, 9.0-15.7. Traill's, 10.2-17.4. Yellow-bellied, 10.3-17.5. Acadian, 13.3-23.5. : : So if you see an eastern empid with a 15mm primary projection, it could be any of them! : : : Hello all, : : I recall seeing a probable Willow Flycatcher in the same area at Barnes last year on Sept. 26 (recall posting 9/27/03). The bird was seen by Brian Rapoza, myself, and a couple of my friends. Even so it's identity was never 100% confirmed, although all field marks led to Willow (particularly comparing distances from base of bill to tip and to eye and also noticing short primary projections) as Brian pointed out. Hey is it me, or does the bird John photographed have longer primary projections than a Willow should have? Hey these ain't fighting words, just an observation. By the way, that is a nice photo John, what's your opinion on the primaries? : : : : Cheers, : : from Arkansas, : : The Rock
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