This dark-backed gull was present at Brownsville Landfill on March
16, 1999 (photos by Martin Reid), and is probably the bird reported
on March 5 as a possible Kelp hybrid. In my opinion the leg color
was perfect for Kelp: a peculiar pale greenish-gray (and uniform
throughout - unlike a minority of other large gulls that show
areas of yellowish-gray and flesh on their legs). The short primary
projection also matches Kelp, but there the similarities end:
The mantle was clearly paler than the primaries and I'd estimate
that the tone was between graellsii and intermedius - about right
for wymani/livens (and thus paler than is apparent in these
computer images); also both the legs and bill are very long
and thin - with a significantly swollen gonys; the single white
mirror would be on the large side for Kelp, and the small patch
of dark brown spotting on the lower nape seems at odds with any
plumage of Kelp.
Thus, I feel it is probably a Kelp x smithsonianus hybrid - and
I arrive at this latter partner because this is the only known
interspecific pairing of Kelp (and from fairly close by, in SW
Louisiana). Could it be something else? - OF COURSE: this is a
GULL! any suggestions/comments
would be much appreciated.
