Photographed by Martin Reid; at East
Beach, Galveston Island, Texas, on March 23, 1999, this bird was
similar in size, shape, and general plumage to an "average"
First-Basic smithsonianus Herring Gull -
see new fully-spread tail pic in the middle - , but.....
- the greater coverts are extremely well-marked, the darker markings
on the whitish lower breast and belly are blotchy bars rather
than a smooth brown wash, the undertail coverts have just three
well-defined, widely-spaced bars on a white background, and the
outer tail feather looks as though it has a lot of white in it....
- the base of the tail is white with numerous fine black bars,
and the lower uppertail coverts have widely-spaced markings -
the tail looks somewhat like a graellsii or michahellis,
but the pale panel in the inner primaries would seem to rule out
those taxa (yes?).....
- a clear black terminal band ending basally in a straight line
level with the tips of the longest uppertail coverts....
- the tertials look plain and dark, but the pale fringes have
been worn off, and from the indented sides and tips, it probably
had a complex white pattern at the tip and along the sides....
- the underwing is similar to smithonianus, but a bit less-uniform
than normal, and within range of, say, a darkish argenteus....
- from this angle the whitish, sparsely-marked uppertail coverts,
white (finely-barred black) tail base and medium-width terminal
black tail band look strongly like many argenteus.
- so why isn't this an argenteus? - it's in Texas! Argenteus
is rarely found south of central/southern France, so it is unlikely
that a vagrant to North America would wander so far south (Galveston
is at the same latitude as the northern Canary Islands). Thus
this bird may be an unusual smithsonianus - and if so a
cautionary tale for those looking for argenteus in N.E. America.
Any comments would be appreciated.