Verification of Unusual
Rec. # 2007-20
|Scientific name:||Empidonax difficilis|
January 16 - 23, 2006, observed on 1/16, 1/17, 1/19, and
1/23. Photographed on 1/23.
|Length of time observed:||5-6 hours|
|Location:||Virgin River, above the Washington Fields Diversion|
|Distance to bird:||3-15 meters|
|Optical equipment:||10 x 42 Leica binoculars, Zeiss 85 T Diascope (20-60x).|
|Light Conditions:||observed under various light conditions from sunlight to complete cloud cover|
|Description: Size of bird:||see below|
|(Description:) Basic Shape:|
|(Description:) Overall Pattern:|
|(Description:) Bill Type:|
Field Marks and
Kristen and I observed an adult Western Flycatcher at the Brinton Pond (along
the Virgin River above the Washington Fields Diversion).
Often present along the pond foraging very low (never higher than ten feet, mostly below 5 feet) along the pond. Occasionally flicks tail upward when perched, never observed flicking wings.
Overall, bright golden above, and very yellow below (chest, belly, flanks, undertail coverts), yellowest down the center of breast and chest. Appeared fairly large-headed, with a slight crest, bold, distinct, teardropped shaped eye-ring, largest behind the eye, and thinnest above the eye. Whitish spot on lores. Bill, large and stout, broad at the base, upper mandible dark and lower mandible bright yellow, gape yellow.
Head (forehead, crown, nape, cheeks) golden green. Wings greyish with distinct wingbars and pale (whitish) tertial and primary edges. Relatively short primary projection. Tail relatively long,
broad, deeply notched and appeard frayed (well worn). Similar in overall color to nearby Ruby-crowned Kinglets, but brighter golden yellow above and below.
|Song or call & method of delivery:||none heard|
|Habitat:||Riparian habitat around spring fed pond in the floodplain of the Virgin River. Vegetation was primarily marsh plants, and willow, tamarisk, cottonwood, arrowhead, rabbitbrush, quailbrush, mesquite, and other typical riparian vegetation.|
were they eliminated:
Elimination: Pacific-slope Flycatcher is indistinguishable from Cordillerean in
the field. Call notes and songs are reported as diagnostic to differentiate
between these two species, however there
is a great deal of overlap in both calls and songs, even on breeding grounds. Very few Western Flycatchers have been documented wintering in the United States, and all those that have been identified to species have been Pacific-slope flycatchers, including many banded along the
lower Colorado River in recent years at Bill Williams NWR, Mojave Co., AZ. In addition, apparently Cordillereans typically winter in high elevation forests in Mexico, and Pacific-slopes winter at lower elevations, along the west Mexico coast, and are often found using riparian habitats in the winter.
this & similar species:
|Familiar with all North American Empidonax Flycatchers, and have observed both species of "Western" Flycatcher throughout their range.|
|References consulted:||I have reviewed all the literature I can find on wintering "Western" Flycatchers in the United States and Northern Mexico, and all that have been further distinguished have been labeled "Pacifi-slope".|
|Description from:||Notes taken at time of sighting|
|Observer's address:||Hurricane, UT|
|Observer's e-mail address:||email@example.com|
|Other observers who independently identified this bird:||Kristen Comella|
All information above is copied directly from field notes taken while observing
the bird (except the similar species discussion).
Interestingly, the only other Empidonax flycatchers that I've observed wintering in Utah (and I can't find any evidence of previous reports) were also observed during January 2006. Merrill Webb, Tim Avery, and I observed an apparent Western Flycatcher at the Red Hills Golf Course on January 15, 2006, and when Tim and I went back later that day to take photos of the bird we found a Dusky Flycatcher (photographed by Tim). I observed both of these birds again on the 17th.
I believe Pacific-slope Flycatcher is a relatively common annual migrant through southwestern Utah. It is the prevailing thought that Pacific-slope Flycatchers migrate through lowland areas of the southwest, while Cordillerean Flycatchers are considered rare in lowland areas during
migration, even within core breeding areas. Based on vocalizations I've heard, I believe the majority of Western Flycatchers using low desert areas during migration in Washington County, Utah are Pacific-slope Flycatchers. I believe this species should be added to the state list.