REPORT #: 75-B-06

Idaho Bird Records Committee Rarities Report Form

Species: Tennessee Warbler

Reporter: Jay Carlisle (I did not see the bird; confirmed ID via photos)

6105 Kirkwood Rd

Boise, ID 83709

jaycarlisle@boisestate.edu

Other Observers: Matt Gracey, Caroline Poli, John Warzybok (all IBO field crew members)

Date Report Prepared: 9-20-06

Date Sighting Occurred: 9-13-06 (capture)

Locality of Observation: Lucky Peak (Boise Foothills), Ada Co.

Habitat: montane deciduous shrubland bordered by coniferous forest

Conditions: calm & clear

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 bill; a bright yellowish/greenish back and head; a distinct, dark eye-line splitting a broken 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: 60mm; Tail: 42mm.

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 750am

How and when did you positively identify the bird, and what clinched the identification for you? I confirmed identification (originally identified in the hand by Matt and confirmed by Caroline and John) after viewing the attached photos. Clinching features included the whitish undertail coverts, bright greenish-yellow coloration to back and head, and the dark eye-line. Additionally, 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 60mm wing is most likely to have a tail measuring 49 or 50 mm (as opposed to 42mm).

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 3 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 Matt Gracey.