These two rather different definitive-alternate Lesser
Black-backed Gulls (Larus fuscus graellsii?) were
photographed by Martin Reid at La Marque, Texas on 3rd of April,
2000. This first bird is fairly typical of most birds seen on
the Texas coast, in that it is just slightly darker than nearby
Laughing Gulls ( at the same angle); it has two primary mirrors
(the one on P10 being large and close to the tip), large white
apical spots on the primaries, black on six outer primaries, and
the tail tip is at a point half-way between the apical spots of
P6 and P7 (not visible in the photos but noted in the field) -
thus a good match for graellsii, albeit a slightly dark
one:
This second bird was seen to be clearly darker that LAGUs at the
same angle, has only one small mirror on P10 that is well-separated
from the tip, small white apical spots on the primaries, black
on seven outer primaries, and the tail tip is level with the apical
spot of P6 - thus a good match for intermedius: ; note
in the image below that there is no white inner border on the
inner web of the black subterminal band on P6 - apparently most
heuglini have such a white border, while most graellsii/intermedius
do not:
although this bird has a small amount of black on the bill, it
may still be a full adult (one LBBG that wintered on the Texas
coast for 10+ years always had some black on its bill).
The eye was palish, but duller than on a normal LBBG (orbital
ring red)
