Hello Rob,


I found this info for you on the Burke website.


Administrator: Given the copyright and credit is listed and the material is being used for educational purposes only, I assume it is OK to replicate on Tweeters. Please inform me if this is not the case.


Dan Reiff
Mercer Island
"Dan Reiff, PhD" <notcalm at comcast.net>;






"Q: Why are there so many crows? What do I do if I see a banded crow?
A: The crow population has increased dramatically in Seattle over the past 40 years. Increases in human population have reduced forest cover, creating open foraging areas preferred by crows, and generated food sources such as garbage that crows are quick to exploit.







The communal roosting of crows at night in the non-breeding season is particularly noticeable and sometimes disruptive. Crows probably roost communally for the same reason many other birds do?to avoid predation and share information about food resources. When crows are breeding, starting in about April in the Seattle area, they disperse onto territories, females stay on nests, and birds are generally less noticeable. However, as winter approaches crows often form huge roosts, where they congregate at sunset. They typically commute along regular flight paths, stopping at traditional pre-roosting sites along the way and often vocalizing loudly. Major roosts can reach truly astounding numbers: up to 2 million birds in places in the Midwest. In the morning, birds disperse and follow each other to foraging sites. In general, larger roosts are associated with greater dispersal distances during the day?birds often fly many miles away to feed. "











?2010 Burke Museum of Natural History and Culture .
All Rights Reserved . Box 353010, University of Washington ,
Seattle, WA 98195-3010, Phone: 206-543-5590.
On the UW campus at 17th Avenue NE and NE 45th Street . University of Washington




























----- Original Message -----
From: "Rob Sandelin" <floriferous at msn.com>
To: "tweeters" <tweeters at u.washington.edu>
Sent: Friday, February 26, 2010 11:22:24 AM GMT -08:00 US/Canada Pacific
Subject: [Tweeters] WHen do crow groups disperse? Or do they?


It has been my loose observation that sometime during the spring these large groups of crows stop congregating and I assume this is due to reproductive pair bonding. But I would be interested in hearing from those who have the regular ability to see these groups as to when they stop seeing them.

Rob Sandelin
Naturalist, Writer, Teacher
Snohomish County
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