English and Scientific names:

Black-whiskered Vireo (Vireo altiloquus barbatulus)

Number of individuals: 

1 in fresh spring plumage 

Locality: LOUISIANA: 

Jefferson Parish

Specific Locality:

TNC Landry-LeBlanc Tract (Sureway Woods) on Post Ln., Grand Isle

Date(s) when observed:

5 April 2008

Time(s) of day when observed:  

~3:45 PM CDT

Reporting observer and address:

Devin Bosler

Baton Rouge, LA

Other observers accompanying reporter who also identified the bird(s):

 

none

Other observers who independently identified the bird(s):

David Muth, Don Norman

Light conditions (position of bird in relation to shade and to direction and amount of light):

Fair w/ optimal afternoon light.  Sun angle relatively high and not a problem.  Sun opposite the bird and behind observer. 

 

Optical equipment: 

Zeiss Victory FL 8x42 (excellent condition)

Distance to bird(s): 

ca. 8-10 meters

Duration of observation:

~1 min.

Habitat: 

Mature coastal, live oak-honey locust-pecan-sugarberry woodlot w/ semi-open canopy and patches of dense understory.  Undergrowth comprised of elderberry-privet-yaupon thickets.

Behavior of bird: 

David Muth alerted me to the vireo’s presence, so I was purposefully searching for it.  The vireo was observed foraging and subsequently resting at the top of a smaller sugarberry.  It was associating w/ a small, migrant feeding flock of vireos and warblers, but remained solitary apart from the group throughout the observation. Then it flew into the canopy of a live oak and couldn’t be relocated.  While trying to obtain video, I lost sight of the bird. 

Description:

A ‘red-eyed’-type vireo w/ dusky green upperparts and pale underparts.  Upperparts appeared more dingy, or grayish-brown than accompanying Red-eyed Vireos.  Sides, flanks, and undertail coverts showed a slight yellow wash typical of fresh spring plumage.  Bold, white supercilium bordered by a black loral stripe (extending through postocular) below and a gray crown above.  A dark malar stripe was very apparent at first glance.  Bill appeared noticeably larger than surrounding Red-eyeds.  Reddish-brown irides and dark tarsi/feet.

 

Presumably barbatulus of coastal FL due to the presence of a distinct white eyebrow and relatively smaller bill.  This ssp. is thought to be the expected spring vagrant to coastal LA (‘overshoots’ or wanderers from FL) based on empirical and specimen data.

Voice:

Silent

Similar species:

Most vireos can be eliminated by the bold, white supercilium bordered by a gray crown above and a complete black loral stripe below.  Red-eyed Vireo (REVI) can be eliminated by the diagnostic, blackish malar stripe, duller olive-green upperparts, and slightly larger bill.  Nominate altiloquus of the Greater Antilles can be ruled out by a conspicuous white supercilium and slightly smaller bill (not as proportionally large as on nominate).

Photographs or tape recordings obtained?

Very brief video, however not diagnosable.  No video/photos attached.

Previous experience with this species: 

Familiar w/ BWVI from a few trips to s. FL and a previous encounter in LA.  One observed at Peveto Beach Woods, E of Johnson Bayou (Cameron) on 1 May 2005.  Most recently observed several individuals singing at Key Largo and Key West, FL (Monroe) on 23,24 Aug 2006.

Identification aids:

National Geographic Complete Birds of N.A. (Alderfer et al. 2005).

This description is written from: 

notes made during the observation

notes made after the observation

memory

Are you positive of your identification? If not, explain: 

 

Yes, very confident.

Reporter: 

Devin Bosler 

Date and time: 

22 April 2008   2:15 PM CDT