The Gulls of Second Avenue

Hi everyone,

I know it's been a while since I gave an update of the
Second Avenue gull colony (for newcomers, I work in a
downtown office building with a great view of a "colony" of
GLAUCOUS-WINGED GULLS that nest on the roof of the building
next door)

Territorial activity dropped off in April. By mid April, it
seemed that the gulls had all established their territories
and there haven't really been any of the dramatic fights
like there were in February and March. There are still
territorial incursions, but the intruding gulls are easily
driven off. Usually the defending pair do a little
"choking" display on the nest, and maybe a small charge.
Intruding gulls are not sticking around to fight. I suspect
that the real heavy fights in February/March are males or
pairs trying to establish their territories; more recent
gulls are casual intruders, just seeing what they can get
away with. However, in past years I have seen some big
fights shortly before laying time, and once the chicks are
fairly large (last year one of Horace and Gertrude's
juveniles would chase off a pair of adult gulls that
little one had spunk!)

Nest building started in late march. I first saw Horace
bringing nest material to nest #1 on 3/28. The pair at nest
#5 started a little earlier, but they had not been
successful at nesting last year, due to construction on the
building next door, so they did not have a large grassy
pile to begin with. Horace and Gertrude's nest from last
year, on the other hand, survived fine and was covered in a
thick mat of green grass. However, nest-building in general
was sporadic during most of April, but really picked up in
the last two weeks.

One interesting thing this year one of the gulls in pair
5 (I think the female, but it is very hard to tell) somehow
got marked with some dark substance paint or oil or
something. It seems to have had no negative affect on her,
but it does give me a clear marker of who she is. I've been
surprised at how far their territory seems to go and how
close they will get to the other nests without seeming to
cause any territorial disputes. (once territories have been
established, the gulls are very tolerant of their neighbors
on the roof, but not of strangers. When an intruding gull
lands anywhere on the roof, one of the roof gulls generally
chases it off, even if it is on the nest-site of another.)

On April 25th, I saw the first mating of the season, with
Horace and Gertrude. Others have been mating since. (Horace
and Gertrude are the gulls that I have the best view of, so
there may be some observer bias). I don't expect
to see any eggs for a couple more weeks (last year H and G
had first eggs on May 20th, the year before May 18th. They
are usually one of the first. Pair 6 had the first eggs two
years ago, but they didn't nest last year due to the worker
activity, and their nest is now concealed where I can't see
it).

Interestingly, several of the times I have seen Horace and
Gertrude mating have been right after a territorial
encounter, where they were both "choking" over the nest. I
wonder if the territorial behavior and the excitement of
defending their nest gets their hormones running?

I wonder also why the gulls nest when they do. Falcons have
hatched already, Bald Eagles lay eggs in March, Herons laid
there eggs weeks ago, but Glaucous-winged gulls don't lay
till late May-June. I suspect it is linked to the fish they
generally eat (during the breeding season Gulls usually
shift from diets of french-fries and junk food to more
nutritious fish, even adjusting their diets depending on
the age of the chicks, if possible). Or perhaps by nesting
as late as they do, they don't need to protect the chicks
from cold weather.

Anyway, I'll let you know when the first eggs are laid.

>From the Second Avenue gull observatory. . .

John Chapman
Downtown Seattle, WA
ragweed at igc.org