Idaho Bird Records Committee Rarities Report Form

Species: Least Flycatcher

Reporter: Jay Carlisle

989 W. Sherwood, Boise, ID 83706

jaycarlisle@boisestate.edu

Other Observers: Caroline Poli, Nathan Banfield, Stephanie Coates (IBO field assistants @ Lucky Peak)

Date Report Prepared: 6-19-10

Date Sighting Occurred: 9-15-09

Locality of Observation: Lucky Peak, Ada Co.

Habitat: mosaic of deciduous shrubs, Douglas-fir forest, and shrub-steppe

Conditions: don’t remember

Did you take notes? No

Did you consult a field guide or other reference work? yes

What guide(s) or reference(s) did you consult? Pyle guide & Sibley

Description: The bird was captured during standardized fall migration banding. It was an immature bird based on plumage (fresh not worn, juvenile shape of tail feathers) and incomplete skull development. Its wing length was 59mm and tail 54mm. As can be seen in the photo, the bird had a brownish cast to its upperparts and a very compact shape – short wing projection, relatively short tail, and a short, somewhat widened bill.

Behavior: N/A.

How and when did you positively identify the bird, and what clinched the identification for you? The diminutive size, short and somewhat wide bill, and brownish cast to plumage separated this bird from the other common Empidonax we capture.

How did you eliminate similar species, and what were they? Other Empidonax flycatchers are all candidates. Of the western Empidonax, the Gray Flycatcher can be eliminated by its larger size, much longer & narrower bill, and grayer coloration. “Western” Flycatchers are much greener on the upperparts. Willow Flycatcher is the most similar in plumage coloration (Least and Willow have the most brown) but they have a much larger bill as well as larger size overall. The two most numerous Empidonax during fall migration @ Lucky Peak are Dusky & Hammond’s. Both have very narrow bill shape and have more green and/or gray than brown in their upperparts. Also, Dusky is characterized by short wing projection and a longer tail while Hammond’s generally has longer wing projection and a shorter tail – both differ from the short wing AND tail of Least.

Experience with this species (and similar species): I have observed 100s to 1000s of all the western Empidonax (and smaller #s of all the eastern species as well) both in the field & in the hand (via migration banding). Thus, I’m very familiar with the plumage and structure of the Empidonax.

General birding experience: extensive; 14+ years in US and Latin America

Were photo(s), video, and/or audio obtained by you? (If yes, please include or attach) Yes – 1 by Nathan Banfield.

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