Michael

Observations I have made a number of times at the Montlake Fill/Center
for Urban Horticulture (CUH) in Seattle is that there seems to be a
consistent pattern of groups of birds coming in from around the area in
a rough sequential pattern. This starts to happen late in the afternoon,
but while there is still sunlight. Typically groups of from 100 to 200
birds will arrive, and start forming up in the area around the CUH and
spilling onto the Fill. The groups arrive from all over the area, with
some groups coming from the direction of the eventual roost on Foster
Island. These groups arrive during about a 1-2 hour period. All groups
seem to "home in" at this gathering spot.

There is much "talking", "squabbling" and general flying around locally
with extensive interaction. I have seen up to 2400 birds in this
gathering. There is not only cawing, but also bill clacking, and very
occasionally an isolated bird doing its low "singing". Usually, shortly
after sunset, or when the light levels begin to drop the gathering
begins to break up with the birds flying toward Foster Island. Makes for
a fascinating afternoon.

During a class with Dennis Paulson, a question was asked as to whether
the members of the groups and subgroups were the same from day to day.
As I remember, Dennis said that was a good question and would be worth
study.

Brian H. Bell
Woodinville WA
bellasoc at isomedia.com