Well the breeding season is getting underway for Glaucous-Winged
Gulls here in downtown Seattle. As in previous years, the level
of activity on my rooftop gull colony has increased considerably
in the past couple of weeks.

For those who are new to the list - I work in an office building
on Second Avenue in downtown Seattle. Outside of my window,
across a small courtyard, there is an older three-story bank
where six pair of Glaucous-Wing and Glaucous-Winged x Western
hybrid Gulls have been nesting for years. In my last post I
reported that some adult gulls had returned to their nest sites
and were showing territorial behavior beginning in mid-November.
The territorial behavior has continued at about the same level
through the winter - gulls occupy the nesting territory much of
the time, but not all the time; there are occasional displays of
territorial behavior, primarily "choking" but also some posturing
and charging that occasionally leads to a few beak-jabs.

In the last couple of weeks, the number of gulls on the roof has
increased, as has the intensity of some of the territorial
behavior. I am seeing more incidents when both members of a pair
are present on their territories, and there have been more
frequent and more intense battles. Usually territorial issues are
settled through body-language and posturing - the defending gull
exhibits "choking" behavior, then goes on to grass-pulling or
other threatening behavior (grass-pulling is sort of meant to
convay "this is what I'm going to do to you"). Finally the
defending gull charges the intruder, who usually takes the hint
and takes off.

Occasionally, however, things get into more of a face off, and
you have the intruder gull (or pair) facing off with the
defending gull/s, both of them "choking" face-to-face. After
several minutes of posturing, one goes after the other
physically, biting at wings, neck or beak. Most intense
territorial battles seem to be among males, though on nest-site
#1 (which is right outside my window and gives me the best view)
at least, the female, Gertrude, has been more active defending
the nest.

On February 23rd, I saw the most intense gull fight I have ever
seen One gull the base of the other's wing in it's beak, while
the other struggled and snapped at wings and tail of the first.
They were going at it for almost ten minutes, tumbling end over
end and flopping all over the little rooftop platform where this
particular nest-site is. Finally, one half-fell, half-flew over
the side and got away. The other (defending?) gull spent a long
time preening it's ruffled feathers. For all the thrashing
around, there was no sign of either blood or significant injury
(which seems to be typical, though the literature reports that
blood is sometimes drawn in these conflicts)

None of the gulls have started to bring nest-building materials
yet, though I have seen nest pair #1 (Horace and Gertrude)
sitting down on last-years nest (which is now covered with
several inches of bright green grass). Horace and Gertrude were
also starting to head-toss, which is part of the courtship ritual
(though mating in earnest won't happen till late March or April
with first eggs laid in mid-May).

When I posted my last report on these gulls, Bob B. shared a
number of observations based on his experience observing Western
Gulls in the SE Farralon Islands. He also asked a number of
questions, which I never did get a chance to answer. One of the
questions was about the level of competition for nest space.
I don't know how it compares to a "wild" colony, but the
competition for nest space seems fairly intense. There are
usually multiple confrontations per day in the colony I watch,
and that is with a lot of human presence (which I will explain in
a moment).

Competition for rooftop nesting space has probably increased in
the last couple years in the immediate area that I watch. In
addition to "my" roof, there are several other buildings around
that host gull nests. There was an empty building on the corner
of Second and Cherry that hosted at least a dozen well-
established pairs. In the fall of 1998 and winter of 1999, that
building was torn down to make way for the Millenium Tower
(currently in construction); the result being that a dozen or so
nesting pairs were without a home.

It was interesting to see how attached the gulls were to their
home territories. They continued to try to claim territory the
entire time the building came down. They would take off during
the day while the actual demolition was going on, then settle
back down on what was left at night. As each floor came down,
they would just land on the next-highest spot, till finally they
were fighting over the dirt at the ground level. Once they
reached ground level, they started looking to the highest objects
around to try to find nest-space - which was the tops of the
bulldozers and power-generator, and the porta-potties. I felt sad
for the pair that thought they were going to nest on top of the
porta-potties - they thought they had the best spot in the place!

Eventually, it did become clear to most of them that their old
nesting spot just wasn't going to work. After a while I began to
notice more nest-building on some less desirable locations.
Several built nests on some narrow ledges and window-sills. I
never saw any of these nests fledge and young, and I suspect the
chicks fell off the narrow ledges.

"My" colony had other disruptions. The building next to the roof
I observe has been doing some sort of major surface repair work,
which has taken more than a year so far. As a result, workers
were out on the roof every day for much of the 1999 nesting
season and at least one territory was completely covered with
scaffolding. Of the six pair that nested here in 1998, only two
were succesful in raising chicks in 1999, and they nested on top
of two access "huts" that stood one story above the rest. One
tried to make a go of it on top of some HVAC ducts, and gave up
before the eggs hatched. The rest gave up before they had any
eggs. They seemed to be able to handle the human disruption
during the early part of nest building, but not when laying time
came.

This year is starting out similarly - they are STILL working on
the building next door, but the gulls seem to be staking out
territory anyway. The work looks like it's almost done, so with
luck they will be able to successfully nest this year. If not,
then I will just have to settle with the two pair that nest on
the access huts, which fortunately includes Horace and Gertrude.

>From Second and Columbia,

John Chapman
Downtown Seattle, Washington
Ragweed at igc.org