Rare Bird Documentation
sterrill@harveyecology.com
Species: Black-whiskered Vireo (Vireo altiloquus)
Date: 12 April 2011
Location: Sureway Woods,
Grand Isle, Jefferson Parish,
Optical Equipment: Swarovski 8.5 X 42
Other Observers: Originally found by Colin Boeh et
al.; Seen also by Ryan (photos) and Linda Terrill and several other observers.
Circumstances: Colin Boeh told us that he had seen a
Black-whiskered Vireo near the junction of the main trail and the entrance road
to Sureway Woods about an hour earlier (around
11:30?). We were working a flock of
migrants at approximately 12:30 that included Blackburnian,
Prairie,
Description: A large, sluggish vireo similar to
nearby Red-eyed Vireos (V. olivaceus) in overall size, shape and plumage. Foraging slow and
deliberate. Pileum
grayish olive grading into olive-brown nape and back (contrast between pileum and nape not so stark as on the Red-eyed Vireos and
olive of upperparts appeared more brownish toned relative to the Red-eyed
Vireos). The overall effect was less
green and gray contrast on the upperparts compared to
Red-eyed Vireos. The bill appeared large
with a pale base to the mandible reminiscent of Yellow-green Vireo (V. flavoviridis). The bird had a dull whitish supercilium
bordered below by blackish eyeline that ran from the
base of the bill to a tapered point behind the eye. The auriculars were olive and the bird showed
a malar stripe. The conspicuousness of
the malar stripe varied with posture and lighting. The throat was off white or grayish white as
was the center of the breast and upper belly.
The sides of the breast and flanks were washed with olive and the
undertail coverts were washed with yellowish.
The tail was rather short and dark gray.
The wings and coverts were similar in color to the back with some lighter
green edgings. Legs
relative robust and dark.
Discussion:
This species is a rare to casual spring migrant to the Gulf coast with
most LA records occurring from mid-April to early June. Evidently, Grand Isle is a very good location
for this species in LA (Ryan Terrill, pers. comm.). It was a delight to see this bird on the Gulf
coast away from breeding grounds in