IDAHO RARE BIRD REPORT FORM
SP--------------------- LOC----------------- DATE-------------- DECISION------------
Species reported: Philadelphia Vireo (Vireo philadelphicus)
Reporter (please include address, phone, e-mail):
Craig R. Fosdick
2511 North 21st St
Boise, Idaho 83702
Cell: (208) 860-6011
Home: (208) 342-7204
e-mail: CraigFosdick@mail.boisestate.edu
Other observers: None.
Date and time of record: 1045 - 1115 AM, August 25, 2004.
Date report prepared: This report prepared October 12 & 27, 2004; original field description prepared on August 25, 2004. Much of this report is simply an edited and formatted version of my original field description from my personal notes as well as my posted message on IBLE.
Locality: Barber Park, Boise, Ada County, Idaho.
Habitat: Dry
riparian zone; mostly, if not all, deciduous.
The riparian zone is located just south of the main "wildlife
area" trail that runs in an east-west direction
through
the middle of the park, and just west of the new parking lot.
Conditions (weather, light, distance, optical aids, duration, etc.): The bird was observed for about 25-30
minutes at close range, generally 10-12 meters away, and at times less than
5 meters. I used Zeiss 7x42 Dialyt
binoculars for the observations. Weather
was clear, calm, perhaps 65-70 F.
Description of bird(s) (size, colors, all field marks
observed, field marks not seen): The bird was smaller than both the
Yellow Warblers and Warbling Vireos that were in the vicinity. However, it was not as slim as say, a Yellow
Warbler. Its tail was quite short,
(much shorter than on a Warbling Vireo) and its bill was rather short, but not
quite stubby and not overly thick.
Noticeable was the crown. It was
darker gray and more contrasting with the bird's white supercilium than on a
Warbling Vireo. Although Sibley mentions dark lores, I did not see them, but I
should note that the bird was very active (and it was raining lightly at the
time of the sighting), so perhaps I did not get the best look at that feature.
The bird's face pattern was very distinctive - dark gray cap, short dark line
behind the eye, contrasting with whitish supercilium. Also, although the bird did not have an eye ring, it was as if
someone had erased the gray in a ring around the eye, to the extent that
although there was not a complete eye ring, only the dark stripe behind the eye
interrupted it. I should also note that
the bird did not have red eyes; the
eyes appeared dark, but not red.
The bird's back was grayish, and its underparts did not
contrast nearly as much with its upperparts as on a Warbling Vireo. Underparts were whitish, with tinges of
yellow wash on the upper breast and in the vent area. However, the wash did not appear as strong or as weak as either
of the two birds depicted in Sibley's Western Guide. Legs were dark. The bird made no vocalizations. There were no wing bars. Plumage appeared fresh, or at least not
overly worn, and there was a pale area at the base of the folded primaries
somewhat reminiscent of the wing spot on a Black-throated Blue Warbler. Perhaps this was the edging on the folded
primaries, as depicted in Sibley?
Behavior of bird(s) (songs, calls, interactions with other birds): No vocalizations were heard. Although the bird was foraging in close enough proximity to several Yellow Warblers and at least one Warbling Vireo, no interactions were observed. The bird appeared to be foraging primarily by gleaning from leaf surfaces no more than 5m from the ground.
List similar species and tell how you eliminated
them:
Red-eyed
Vireo: (1) Tail was too short, much shorter than on a REVI; (2)
wrong bill structure for REVI: bill was rather short, but not quite stubby and
not overly thick; REVI’s have relatively long, stout, bills; (3) The crown color
was similar to that of a REVI, but lacked the blackish edging on either side of
the crown present on a REVI, where the crown meets the supercilium; (4) the bird
was too small for REVI; it was similar in size to the Yellow Warblers and
Warbling Vireos it was feeding with; (5) the bird had dark, not red eyes; (6) the
bird’s head structure was incorrect for REVI; REVI have a flattened head,
irrespective of whether crown feathers are raised (if bird is agitated); this
bird had a smooth, rounded head.
Warbling
Vireo: (1) Tail was too short, much shorter than on a WAVI; (2) the
bird had the wrong bill structure for a WAVI: the bill was rather short, but
not quite stubby and not overly thick; (3) the bird’s crown was darker gray
than on a WAVI, and there was too much contrast with the white supercilium for
a WAVI; (4) the bird was too small for a WAVI.
Blue-headed,
Cassin’s & Plumbeous
Vireo: (1) Facial plumage alone rules out all of
these species; all have bold white spectacles that contrast with gray (CAVI
& PLVI) or slate-blue (BHVI) hoods; this bird did had an incomplete eye
ring, not the bold spectacles characteristic of a BHVI, PLVI or CAVI. Moreover, the bird's face pattern was very
distinctive, and not at all like that of BHVI, PLVI or CAVI; this bird had a
dark gray cap (not a hood), a short
dark line behind the eye that contrasted with its whitish supercilium; (2) Also,
this bird had no wing bars, which are present in BHVI, PLVI and CAVI; (3)
Finally, this bird’s bill was too small for either BHVI, PLVI or CAVI.
Gray
Vireo: (1) Gray Vireos
are basically entirely gray with no contrast in plumage; (2) this bird had a
short tail, not a long tail that is actively flipped about as in GRVI.
Hutton’s
Vireo: (1) HUVI has no contrasting cap, which this bird had; (2) HUVI
have two wingbars; (3) HUVI eyering is incomplete; with broken area above and
below eyes, whereas this bird had an incomplete eyering with broken area behind and in front of eye; also, this
bird had dark line behind eye, which HUVI’s lack.
Bell’s
Vireo: (1) This bird did have bill structure and a broken eye-ring similar
to that of a BEVI; however, BEVI does not have a contrasting cap, which this
bird did have; (2) this bird had a short tail, about half as long as its folded
wings; not a very long tail, as in a BEVI. BEVI tail is nearly as long as the bird
itself; (3) this bird had no wing bars; according to Sibley, even drab worn
adults should show a trace of wingbars; and finally (4) bright eastern BEVI’s
might seem like a possible match because of their coloration, but they still
have wing bars, lack a contrasting cap, and still have a very long tail.
*Thick-billed Vireo, White-eyed Vireo, Black-capped Vireo,
Yellow-throated Vireo, Yellow-green Vireo, Black-whiskered Vireo were not considered per se, but the above description & species-specific
comparisons rules them out*
What is your experience with this or similar
species?). I have prior experience with Philadelphia
Vireo, having seen it several times in migration in upstate New York, as well
as singing territorial birds on the breeding grounds in northern
Maine. I also have extensive experience with
Red-eyed, Warbling, Blue-headed and Cassin’s Vireo, both on the breeding
grounds, and in migration.
I spent nearly a decade working & birding in the
northeast (New York & Maine), and a summer in northeastern Minnesota &
Wisconsin (1995), so I am quite familiar with identification of Red-eyed,
Warbling, and Blue-headed Vireos by both sight and sound (songs and calls). All three species are relatively common to
abundant both in the northeast, as well as in Minnesota & Wisconsin. From 1996 onward, I have spent nearly nine
consecutive summers studying breeding bird communities in forested habitats of
Idaho and northeast Oregon. This
research involved hundreds of avian point-count censuses, as well as hundreds
of hours of nest-searching (including nests of both Cassin’s and Warbling
Vireo). Thus, I have extensive
experience with Cassin’s Vireo, as well as more experience with Warbling Vireo.
I have limited experience with both Bell’s Vireo and Gray
Vireo. I have seen and heard Gray Vireo
on the breeding grounds, in Canyonlands National Park, southern Utah. I have seen and heard singing Bell’s Vireos
in southeastern New Mexico.
Were photos obtained? (please enclose if possible). No photos were taken, as I was not carrying a camera.