English and Scientific names:

Great Black-backed Gull (Larus marinus)

Number of individuals: 

1 near-adult; probable 3rd basic

Locality: LOUISIANA: 

Jefferson Parish

Specific Locality:

Grand Isle; shell road by Exxon fields

Date(s) when observed:

13 April, 2007

Time(s) of day when observed:  

5:45-6:00 p.m.

Reporting observer and address:

Phillip Wallace

New Orleans, LA

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


Curt Sorrells

Other observers who independently identified the bird(s):

Devin and Justin Bosler, and other observers at Grand Isle Migratory Bird Festival

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

Good light; sun low at right angle to line of sight.

Optical equipment: 

Zeiss 10x40 bins

Distance to bird(s): 

15-25 m

Duration of observation:

15 minutes


Shell road adjacent to collecting pond and open fields; 200-300 m from the gulf

Behavior of bird: 

Feeding; agonistic behavior toward other gulls; flying.


Larger than adjacent Herring Gulls but not especially large for the species. White underparts and head. Sparse dark streaks on nape. Tail white except for small grayish-black smudge on tail. Black mantle and back. Wings same black color as mantle except for some brownish tinge to primaries and primary coverts; one white mirror on P10. Large, blocky head. Legs pinkish with some ivory tones. Large bill yellowish with red and black smudge at tip. Iris pale but not as pale as full adult.   


Vocalized twice. Voice lower than Herring Gull.

Similar species:

Size, black back, and pinkish legs rule out all other gulls.

Photographs or tape recordings obtained?

Stills grabbed from video accompany this report; video submitted to LBRC.

Previous experience with this species: 

I've seen numerous times in LA and on east coast.

Identification aids:


This description is written from: 

Notes written at 8:30 p.m. on 13 April and from video.

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




Phillip Wallace

Date and time: 

9 June, 2007