RECORD #: 5-A-05

IDAHO RARE BIRD REPORT FORM

SP--------------------- LOC----------------- DATE-------------- DECISION-----------------

Species reported: Connecticut Warbler (Oporornis agilis)

Date and time of record: Aug 30, 2005; 800am

Reporter: Jay Carlisle, Idaho Bird Observatory, Boise State University, 1910 University Ave., Boise, ID 83725; jaycarlisle@boisestate.edu

Other observers: Craig Fosdick, Debbie Leick, Michelle Labbe (all seasonal field assistants at IBO)

Date report prepared: Dec 12, 2005

Locality: Camas National Wildlife Refuge (NWR), Jefferson Co.

Habitat: riparian woodland oasis (surrounded by desert and agriculture) at about 4800’

Conditions: Sunny with mild temperatures; light winds. The bird was captured and banded – thus seen very close. We had the bird in hand for about 15 minutes before release.

Did you takes notes? No.

Did you consult a field guide or other reference work? If so, which guide(s)? During observation: National Geographic and the Peterson Guide to Warblers

Description of bird: This was a chunky, short-tailed warbler with a complete and distinct eye-ring. The bird was about 5.5", had a wing chord of 66mm and tail length of 48mm, and the bird weighed 12.1 grams. This bird had a primarily brown head and chest (creating a hooded appearance), yellow underparts, and a greenish back. The bird had no wing bars, had a short-appearing tail, and long undertail feathers ….. no important field marks were missed. Our determination was that this bird was likely a hatch-year (immature – based on incomplete skull ossification and plumage) female Connecticut Warbler based on the solid brown coloration.

Behavior of bird: only observed in the hand.

How and when did you positively identify the bird, and what clinched the identification for you? Debbie (field assistant) retrieved the bird from the net, placed it in a cloth carrying bag, and brought it to my attention. Before I pulled the bird from the bag, Debbie mentioned she thought it was something different – like a Common Yellowthroat (a species we had banded in the week prior to this capture) but chunkier and with a very distinct eye-ring. I knew it was a Connecticut right away as I pulled the bird from the bag (as did Craig Fosdick – an experienced birder – as I showed him) and clinching ID features included the brownish hood, the bold eye-ring, and the chunky and short-tailed appearance.

List similar species and how you eliminated them: similar species include MacGillivray’s Warbler (Oporornis tolmiei), Mourning Warbler (Oporornis philadelphia), and Common Yellowthroat (Geothlypis thrichas). The three Oporornis species in question are all characterized by a hooded appearance (ranging from brown to blueish-gray), yellow underparts, and a greenish back. Physical features that differ aming species include the extent, shape, and boldness of the eye-ring and overall shape. MacGillivray’s are characterized by a broken eye-ring and this is apparent in all age/sex classes whereas Mourning Warblers usually have no eye-ring, although some (especially immature birds and females) have a narrow, indistinct eye-ring. Also, both of these species have relatively longer tails and shorter undertail coverts than Connecticuts. Female/immature Common Yellowthroats are smaller and slimmer than Oporornis species, they are primarily brown on the back, and their eye-rings are much less distinct.

What is your experience with this or similar species? I have observed only a few individual Connecticut Warblers (Minnesota, SD) but have extensive experience with the other Oporornis and Common Yellowthroats throughout the US (especially ID and SD). MacGillivray’s are among the most common warblers observed and captured in Idaho and I am very familiar with all age/sex classes of this species.

Describe your general birding experience: I have been birding for 16 years; avidly for at least 12 of those. This birding has occurred in the US and in 4 Latin American countries (Mexico, Costa Rica, Panama, Peru). I have seen about 660 species in the US and over 1000 more species elsewhere. I have extensive experience with North American warblers in all plumages and on breeding and wintering grounds and during migration.

Were photos, video, and/or audio obtained? Yes, Craig Fosdick obtained several photos. They are on slide film and I am working to obtain digital copies.

(Representative PHOTO submitted)