I found the bird and no one else was able to observe it.
LOCALITY OF OBSERVATION
Idaho State University campus beside the library in Pocatello, ID. Specifically at: 42.863978, -112.431819.
HABITAT WHERE THE BIRD WAS OBSERVED
The bird was observed in a small patch of conifers bordered by buildings and a small grassy area.
SIGHTING DURATION, CONDITIONS, and EQUIPMENT USED
I observed the bird for about 10 minutes at distances between 10-30 feet with naked eye and Alpen 10x42 binoculars. The weather was warm and sunny with little clouds and very slight breeze. There was patches of snow on the ground.
DID YOU TAKE NOTES?
Yes, later the same day
DID YOU CONSULT A FIELD GUIDE OR OTHER REFERENCE WORK?
Yes, later the same day
WHICH GUIDE(S) OR REFERENCE(S): DID YOU CONSULT?
Sibley Guide to Birds of North America iphone app and The Warbler Guide by Scott Whittle and Tom Stephenson.
DESCRIPTION OF THE BIRD(s)
Classic warbler look with small size, thin bill, and bright colors. The bird can be described as a relatively small warbler lacking any streaking, having blue-gray wings with two thin white wing bars, bright olive green back, olive-tinged gray head and neck, white eye arcs, yellow throat and breast, white belly, and white underside of the tail with small black corners.
BEHAVIOR OF THE BIRD(s)
I observed the bird forage somewhat frantically throughout the conifers, searching along the needles and bark. It worked the conifers thoroughly, giving a high-pitched 'seet' call periodically, and moved to a row of cedars and then flew about 50 meters away to another patch of conifers.
HOW AND WHEN DID YOU POSITIVELY IDENTIFY THE BIRD, AND WHAT CLINCHED THE IDENTIFICATION FOR YOU?
I first saw the bird and thought it was possibly a kinglet because it was moving so quickly and it appeared relatively small and short-tailed. I approached the bird and it foraged very close to me where I quickly noticed the bright yellow below, blue-gray-green upperpart coloration, and white eye arcs. The bird also lacked streaking entirely. This combo clinched the identification for me.
HOW DID YOU ELIMINATE SIMILAR SPECIES? WHAT WERE THEY?
This combination of field marks and the smaller size of the warbler are quite distinctive. The more common Yellow-rumped Warbler was ruled out by the lack of bright yellow rump, isolated yellow flanks, streaking, and lack of overall tan coloration present in late-fall Yellow-rumped Warblers. The possibility of an unlikely Orange-crowned Warbler was ruled out by the presence of white wing bars and bright yellow breast and throat. Also, Orange-crowneds would show extreme uniformity in overall olive-gray coloration, which is not present in this bird.
WHAT IS YOUR EXPERIENCE WITH THIS (AND SIMILAR) SPECIES?
This is the first time I have observed this species but I have read about them and seen many photos beforehand. My experience with all Idaho warbler species is extensive.
DESCRIBE YOUR GENERAL BIRDING EXPERIENCE
Extensive and advanced, particularly in the Intermountain West. I have been avidly birding for about 10 years.
WERE PHOTO(S), VIDEO, AND/OR AUDIO OBTAINED FROM THIS SIGHTING?
FIRST ROUND VOTING:
Description and photos support identification of Northern Parula
Well described - good photos
Well documented with diagnostic pics and good written details.
I agree that this was a HY Northern Parula.
photos are good
An excellent description, as well as a decent comparison to at least a couple of potential other candidates, though would have like to had a comparison to Pine Warbler (Setophaga pinus) given the time of the year. In addition to plumage, the observer also mentions size and behavior characteristics supportive of Northern Parula (Setophaga americana). Oh yeah, I guess the diagnostic phos help too – great Winter find!