|> I'm told that the pinkness of the Ross's Gull is the result of something
|> in its diet. Can anyone comment on this? Especially, how does a diet item
|> translate into feather color? (Forgive me if there's an earlier post that
|> explains all this.) Thanks in advance.
|>
|> Harriet Whitehead
|> Pullman, WA
|> whitehea at wsuaix.csc.wsu.edu

"The pink coloration on some species of gulls (and terns), usually more
prominent on adult summer plumage, is apparently not caused by feather
pigmentation but is said to be the result of pink colorant contained in the
preen-gland oil being coated onto the feathers during preening. The pink
coloration may pervade all parts of the plumage but shows up most on those
areas, especially the underparts, which start out white when the feathers
were newly grown. [..] It is probable that the diet and the degree of
breeding condition affects the strength of the colorant in the preen-gland
oil, and variation in these factors presumably results in individual
coloration in the strength of colour on 'pink gulls' such as Ross' and
Slender-billed. Pale pink tones are often not evident at long range or
in bright sunlight, and are best discerned at close range in overcast
conditions ..." P.J. Grant, "GULLS: A Guide to Identification" (1986), p.20.

Daan Sandee sandee at cmns.think.com
Mountain View, CA 94041