Lizz, Sandra, and Tweeters,

The gathering of Robins Lizz described is almost certainly a
pre-roosting congregation. The giveaway is that it occurs every day
about 5 P.M. American Robins are highly gregarious outside the
breeding season, and like other birds such as European Starlings and
American or Northwestern Crows, usually sleep at night in communal
roosts. These roosts can include hundreds or (infrequently) thousands
of Robins, but are not usually as large or conspicuous as the
night-time roosts of Starlings or Crows. Trees with dense foliage are
preferred for roosting; a densely-foliaged pine tree would do fine.

In the mid-1960s, I studied nocturnal roosts of Starlings in
Vancouver, B.C. At that time, Starlings had been wintering in large
numbers for less than a decade. The two largest fall Starling roosts I
found, both with over 30,000 Starlings, were both in young Red Alder
stands with very dense foliage. Both of these roosts had hundreds of
Robins roosting around the edges, with the Starlings in a dense group
in the interior of the wooded area. I speculated that the Starlings
had been attracted to these roosting sites by the Robins, but they
roosted in such dense groups that the Robins were pushed to the edges
of these alder stands.

The behavior observed by Sandra Andersen sounds like a totally
different phenomenon-- especially if it was not close to sunset. It
sounds like a migratory concentration of Robins. I found in my
Vancouver studies of urban birds that most of the Robins breeding in
residential areas arrived between February 14 and February 28.
However, Robins are common enough in many areas in mid-winter, and
very gregarious, so Sandra's birds could just as easily have been a
winter feeding flock.

Wayne C. Weber
114-525 Dalgleish Drive
Kamloops, B.C. V2C 6E4
Phone: (250) 377-8865
wayne_weber at bc.sympatico.ca


-----Original Message-----
From: E. Kopecek <lizzz at u.washington.edu>
To: Sandra C. Andersen. <scadane at email.msn.com>
Cc: tweeters <tweeters at u.washington.edu>
Date: Friday, February 11, 2000 8:53 AM
Subject: Re: spring sightings , robins


>I'm glad you brought up this Robin congregating question. I work at
the
>UW and our UPS guy that picks up our packages every evening about
5:00 has
>noticed the robins will start flocking together arund then. They all
seem
>to like a large pine right next to Smith Hall and just show up in
droves
>flying around on the inside of it and making alot of fuss. It's
similar
>to the behavior of crows I've seen doing this in huge flocks at the
>Montlake Fill. Can anyone explain this? I told the UPS fellow I
would
>check with everyone out there in birdland and see what I could find
out
>for him. Thanks - Lizz
>
>*********************************************************************
*********
>
>Lizz Kopecek
>History Dept.
>University of Washington
>206-543-5790
>lizzz at u.washington.edu
>
>On Fri, 11 Feb 2000, Sandra C. Andersen. wrote:
>
>> On Capitol Hill , the West side of Broadway in the past two days ,a
two
>> block area was covered with robins, at least one in every
tree/shrub,roof
>> top, no real "singing" or displays, just a whole mess of robins. I
saw
>> something like this two years ago at Montlake Fill, where the
robins were on
>> any branch/twig that could hold them, one even landed on me( I
stood quite
>> still) but those where singing and quite active.
>> Sandi
>> Capitol Hill
>> scadane at msn.com
>>
>>
>>
>>
>