Subject: DENSE COOT FLOCKS
Date: Dec 7 10:17:56 2000
From: Grant Hendrickson - granth at halcyon.com


Wayne's explanation makes particularly good sense for this location on Lake
Sammammish. We have two resident adult bald eagles which spend a great deal
of time perched a the top of a very tall conifer which is several hundred
yards from the area where the coots congregate. Unfortunately, we can't test
the theory because when the eagles take off from the tree, they drop out of
our sight if they drop down to the lake.

Grant Hendrickson
Redmond,WA
granth at halcyon.com

> From: "WAYNE WEBER" <WAYNE_WEBER at bc.sympatico.ca>
> Date: Thu, 7 Dec 2000 07:57:06 -0800
> To: "GRANT HENDRICKSON" <granth at halcyon.com>, "TWEETERS"
> <tweeters at u.washington.edu>
> Subject: DENSE COOT FLOCKS
>
> Grant and Tweeters,
>
> I have always assumed that the reason coots typically aggregate in
> dense flocks in the winter is for protection from predators--
> especially Bald Eagles. On Okanagan Lake in south-central B.C., where
> many thousands of coots winter each year, Bald Eagle attacks on coots
> are frequent (and frequently successful). Coots, unlike ducks, are
> slow to take off and are not agile in the air, preferring to escape
> aerial predators by diving. Gathering in dense flocks seems to give
> them some protection from eagles, in the same way that formation of
> dense flocks helps to protect Dunlin from Peregrine Falcons and other
> raptors.
>
> Wayne C. Weber
> Kamloops, BC
> wayne_weber at bc.sympatico.ca
>
>