Rare Bird Report #: 77-B-06

Idaho Bird Records Committee Rarities Report Form

Species: Tennessee Warbler

Reporter: Jay Carlisle

6105 Kirkwood Rd

Boise, ID 83709

jaycarlisle@boisestate.edu

Other Observers: Stephanie Eyes, Erin Kiely, Chad Merkley (all IBO field crew members)

Date Report Prepared: 9-20-06

Date Sighting Occurred: 8-25-06 (capture)

Locality of Observation: Camas NWR headquarters, Jefferson Co.

Habitat: riparian woodland

Conditions: partly cloudy to start then clearing through the morning; 70’ F by noon

Did you take notes? not at all

Did you consult a field guide or other reference work? during the observation

What guide(s) or reference(s) did you consult?

Pyle’s 1997 ‘The Identification Guide to North American Birds’, Sibley, National Geographic

Description: A small Vermivora warbler with a slender & slightly de-curved bill; a bright yellowish/greenish back and head; a distinct, dark eye-line splitting a broken, whitish eye-ring; a yellow wash on the throat, upper chest, and flanks; whitish undertail coverts and belly; and a relatively short tail (as compared to similar appearing Vermivora warblers like Orange-crowned). Wing: 59mm; Tail: 41mm.

Based on incomplete skull development and plumage, this bird was identified as an immature (hatch-year).

Behavior: none observed as this was a bird captured as part of a standardized bird migration study at 840am

How and when did you positively identify the bird, and what clinched the identification for you? Immediately upon pulling the bird from its cotton holding bag and clinching features included the whitish undertail coverts, bright greenish-yellow coloration to back and head, and the dark eye-line. Additionally, after measuring the bird, the relatively short tail was another diagnostic field mark.

How did you eliminate similar species, and what were they? Orange-crowned Warbler (always has yellow undertail) is the most likely to be confused with this species, especially for immature Tennessee Warblers which are a brighter yellow than all subspecies of Orange-crowned. However, the combination of the features mentioned in the above section all help to separate from Orange-crowned and other Vermivora species. Additionally, Orange-crowned Warblers have a longer tail and an Orange-crowned Warbler with a 59mm wing is most likely to have a tail measuring 48 or 49mm (as opposed to 41mm).

Experience with this species (and similar species): I have observed many hundreds, if not thousands, of each during migration and winter in both the US (especially South Dakota for Tennessee) and Mexico (Orange-crowned) and Central America (Tennessee). I have also previously captured and handled 2 immature and 2 adult (1 male & 1 female) Tennessee during fall migration at Lucky Peak and Camas NWR along with well over 1000 individuals of Orange-crowned Warbler in Idaho.

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, but not by me. See attached photos taken by Erin Kiely.