Thanks Chuck; that seems to make a lot more sense! I couldn't recall
seeing any pair-related behavior before, but for some reason aggression
didn't come to mind. Sometimes it just takes more than one brain I
guess. I can very easily imagine another hummer seeing it, zooming in to
chase it off, and then surprise--this intruder won't leave even when I
make contact! and then repeating the behavior hoping to get the more
typical reaction. I'll suggest moving the feeders farther from the
house.

I love brainstorming about animal behavior and evolutionary puzzles.
Thanks again.
Angela Percival
Olympia, WA
angela at stillwatersci dotcom

------------------------------

Message: 3
Date: Wed, 26 Nov 2008 15:24:33 -0800
From: "Chuck Reinsch" <creinsch at humbirds.org>
Subject: Re: [Tweeters] odd Anna's Hummingbird behavior

Hummers, especially juveniles, have a powerful curiosity (probably helps
in
locating food sources, but puts them in risky situations too), and they
(especially males) are intensely territoriual. Recognizing that it is
very
hard to talk about animal behavior without anthropomorphizing, I suspect
the
one that landed on the stunned bird was just trying to intimidate it
into
leaving the vicinity of the feeder.

chuck reinsch, magnolia, seattle, wa, (creinsch at humbirds.org)