Wayne,

Thanks for mentioning the research aspect of such roosts. I meant to say something about that and forgot.

The Nickerson St. roost cries out for such a study. Almost the entire roost is visible from one place, the birds mostly roost in quite exposed positions, they are big and black so easily counted, and evening or morning photos of each section of the roost would provide abundant data on roost height and positioning that could be analyzed in the comfort of your home. More than one photo taken at intervals would show if there was any pattern in early-arriving vs. late-arriving roost sites. The birds come from both directions along the canal, and that could be monitored as well. Are more of them coming from salt or fresh water? Do adults arrive at different times or from different directions than immatures? Do the different age stages perch in similar places? Do perch sites differ with temperature and weather conditions? I couldn't imagine what those birds would do in a high wind, as they were really exposed. Etc.

This would be a great student project, as you say.

Dennis

On Mar 23, 2012, at 10:24 AM, Wayne Weber wrote:

> Dennis and Tweeters,
>
> There is another very conspicuous cormorant roost in Mount Vernon, close to
> the downtown area, on cables across the Skagit River just north of the
> Division Street bridge (State Route 536). This nocturnal roost has been
> active for more than a decade, and sometimes holds 200 or more birds. It is
> easily seen from Interstate 5 northbound or southbound, although I don't
> recommend watching birds while driving! I estimated 70 cormorants there on
> March 8th just after sunset.
>
> Communal roosts make a good subject for a small-scale scientific study, such
> as an undergraduate thesis or research project. One can keep track of how
> the number of birds changes according to the season, the times that they
> arrive in the evening or leave in the morning, etc. The first serious
> scientific study that I did was a B.Sc. honours thesis on Starling roosts in
> and around Vancouver, BC, and communal roosting is still a subject that I
> find fascinating.
>
> Wayne C. Weber
> Delta, BC
> contopus at telus.net
>
>
>
>
> -----Original Message-----
> From: tweeters-bounces at mailman1.u.washington.edu
> [mailto:tweeters-bounces at mailman1.u.washington.edu] On Behalf Of Dennis
> Paulson
> Sent: March-23-12 9:33 AM
> To: TWEETERS tweeters
> Subject: [Tweeters] Seattle cormorant roost
>
> I know this has been mentioned before, but it deserves more attention. I
> just happened to be on Nickerson St. in Seattle late yesterday afternoon
> (6:15 pm), and I parked next to the ship canal at 180 Nickerson to attend a
> meeting. As we exited the car, we realized there was an ornithological event
> going on right there. Double-crested Cormorants were coming in to roost in
> the poplars adjacent to the canal, and it was a real treat to watch them.
>
> One after another bird came in to land in the branches of these tall
> leafless trees. Sometimes they would make it, sometimes they wouldn't and
> either miss completely or land and then fall off the branch, presumably
> because they couldn't get a good enough grip with those big totipalmate
> feet. Sometimes one would land next to another one and actually knock it off
> its perch or promote a squabble that ended with one bird moving down the
> branch or even flying off. Some birds spontaneously flew out from the roost
> and circled around, perhaps to get a better perch on a second try. Mostly
> they were spaced out well apart from one another.
>
> Watching the birds come in to land was a lesson in aerial agility (or lack
> thereof). These are big birds coming in at speed, and the branches are
> rather slender, many of them angled well away from horizontal. You could see
> a variety of strategies to accomplish the rather awkward landing. It was
> quite cold although fortunately not raining, and we stood outside for 15
> minutes and were in turn amused, amazed, and appalled. It's not a great
> place for photography, as the daylight is dimming, but it was reasonably
> light when birds started to come in, and it would be brighter on a sunny
> evening. A person on an adjacent roof with a long lens could have great
> opportunities. By the time we left, after dark, it looked as if well over
> 100 birds were there. Perhaps they sleep in in the morning for additional
> views and photography, but it will have to be less entertaining than the
> evening arrivals.
>
> This spot deserves a daily influx of birders to watch the spectacle. Don't
> stand directly below them, but by all means check out the show!
>
> Dennis
> -----
> Dennis Paulson
> 1724 NE 98 St.
> Seattle, WA 98115
> 206-528-1382
> dennispaulson at comcast.net
>
>
>
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>
>

-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net