English and Scientific names:

California Gull (Larus californicus)

Number of individuals: 

1 basic adult (presumed albertaensis by size, plumage, etc.)

Locality: LOUISIANA: 

Cameron Parish

Specific Locality:

Broussard Beach, ca. 3 mi. SE of Cameron

Date(s) when observed:

1 November 2008

Time(s) of day when observed:  

~5:30 PM CDT

Reporting observer and address:

Devin Bosler

Baton Rouge, LA

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

 

No

Other observers who independently identified the bird(s):

No

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

Fair w/ clear sky and good, late afternoon sunlight.  Sun lowering on western horizon behind observer.  Backlighting or glare not a factor. 

Optical equipment: 

Zeiss Victory FL 8x42 (excellent condition), Nikon Fieldscope (fair condition), Canon Powershot SD1100 IS (excellent condition)

Distance to bird(s): 

ca. 75-150 meters

Duration of observation:

~10 min.

Habitat: 

Open beach on Gulf of Mexico.

Behavior of bird: 

The gull was resting and preening at the water’s edge amid a very large group of larids.  As is the case with most large gulls, it was exceedingly wary and did not allow close approach.  Nearly the entire group took flight at one point, and the gull was never relocated.  Apparently this individual arrived with the first massive incursion of American Herring Gulls this fall.

 

Description:

A medium to large white-headed gull w/ medium gray mantle.  Decidedly long-billed and long-winged as compared to other large gulls.  Fairly distinct white apical spots visible on folded wing (mirrors on P9-10).  Crown and nape lightly streaked, but otherwise clean white forehead, throat and breast.  Bill bright yellow, longish and parallel-sided w/ minimal gonydeal angle.  Conspicuous black and red markings on gonys.  Dark brown iris and pale greenish-yellow legs and feet.  Larger size and larger white mirror on P10 suggestive of interior-breeding albertaensis.  This ssp. is the expected vagrant in LA.  Only observed at rest; not seen in flight. 

Voice:

Silent

Similar species:

Noticeably smaller than American Herring Gull (AMHG) and larger than Ring-billed Gull (RBGU).  Medium gray mantle was darker than either AMHG or RBGU.  Relatively long, bright yellow bill w/ red and black gony spots diagnostic of CAGU and wrong for AMHG and RBGU.  Dark brown iris and pale greenish-yellow legs are wrong for both AMHG and RBGU at this age.  No other similar gulls to compare.

Photographs or tape recordings obtained?

Digiscoped photographs by Devin Bosler.  Yes, attached.

Previous experience with this species: 

Moderate experience from several western states.  On a few trips to the west coast, I have observed hundreds from WA south to CA.  Also inland at ID/MT and NM.

Identification aids:

National Geographic Complete Birds of N.A. (Alderfer et al. 2005), Gulls of the Americas (Howell and Dunn 2007)

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

Reporter: 

Devin Bosler 

Date and time: 

14 November 2008  10:30 PM CST