Subject: Eagles and Herons nesting disturbance
Date: Jun 7 09:14:28 1996
From: Ter Ellingson - ellingsn at u.washington.edu


I've seen eagles (and red-taled hawks) make tentative forays into
heronries/rookeries on several occasions. The herons have reacted in
either of 2 ways: 1) by standing up in their nests in postures like they
yse for territorial defense against other herons approaching their nests
(neck and crest feathers erect, neck extended, slashing motions with bill
in direction of intruder, etc. - I've been able to photograph one such
interaction at Federal Way a couple of years ago); and 2) by a mass
takeoff and circular group flight in the airspace around the rookery and
the intruder (saw a particularly impressive example of this at Nisqually
last year). This isn't "mobbing" like you see with crows and eagles, no
close approach or direct attack. Maybe something like the way a group of
coots respond to an eagle attack - by fast, mass action that
seems to create confusion and distracts the eagle from concentrating on
any single target? I've seen the tactic apparently work even when two
eagles cooperate on a coot hunt...