Subject: Juvenile Ring-billed Gull
Date: Aug 14 12:04:00 1995
From: "Gates, Bryan" - BGATES at assessment.env.gov.bc.ca


On July 28, Alvaro opened a thread on changing bill colours in juvenile gulls
(California Gulls). Here is another.

On Aug. 13 at River Jordan on the SE coast of Vancouver Island, I scanned
through a close flock of 500+ Californias to find 4 Heermann's and a single
juvenile bird that I suspect was a Ring-billed. However, bill colour was not
like any reference books I have. Ring-bills are uncommon to rare here on the
S. tip of the Island, so I am less than familiar with them.

The bird was smaller, more petite, more streamlined, and noticeably lighter
in overall colour than the juvenile Californias immediately beside it.
Primaries extended well beyond the tail and were blackish. Only a few dark
(brownish) feathers interrupted an otherwise whitish breast/belly. The mantle
was typical of any juvenile gull, showing no light gray "adult" or
first winter feathers, but again was much paler than those of the juv.
Californias. Legs and tail were not visible. On the basis of
characteristics seen, I'm satisfied that this was a Ring-bill.

However, the bill puzzles me. It was definitely smaller and thinner
(vertically) than those of the Californias, had a blackish tip, but a
definite _bright red mottling_ on the basal half. Books show the juv. with a
pale pink or yellowish base, but not red. This was not a stain or blood. Is
there a brief stage in the development of some or all Ring-bill juveniles
when red appears on the bill?

BTW, the bills of all juv. California's in the group were pale at the base
and black at the tip, but showed various degrees of paleness, as might be
expected in mid August.

Bryan Gates, Victoria
bgates at assessment.env.gov.bc.ca