After reading Narendra's message, I thought someone would
comment on the dual nature of dive displays by Anna's
hummingbirds. I would add that the shuttle flight display
Mike is describing is also used for both defense of feeding
territories and courtship. I've only seen Anna's perform
the shuttle flight twice: once in front of a house finch;
once in front of a siskin. I can't comment on it's use in
courtship except to say most references attribute the
shuttle flight to courtship behavior.

The target of hummingbird displays can be other species of
birds, even people. "He was doing it right above my head"
sounds like Narendra was probably the target if the Anna's
display. I've been the target of an Anna's dive display,
and have also seen them dive at and run off a targeted scrub
jay more than once. It's quite a loud, explosive sound
accompanied by an incredibly fast, little green blur.

The only real way to tell if either display is being used in
courtship is to see if the performance is targeted at a
female conspecific.

David Tracy
dtracy at richardloschinc.com
Bend, OR
----- Original Message -----
From: Mike Patterson <celata at pacifier.com>
To: <narendraabhagwat at hotmail.com>
Cc: <TWEETERS at u.washington.edu>
Sent: Monday, October 23, 2000 4:25 PM
Subject: Re: Anna's courtship display at Montlake
fill,banded crow


> These full sized hummer displays are more properly called
territorial
> displays. They are routinely used to denote feeding
territories and
> need not be associated with the breeding season. Most
hummingbirds
> (Anna's included) have much more intimate displays;
whisking and
> figure-eights that are almost entirely used for courtship.
>
> There's been a lot of comment about Sibley's new book, but
one things
> that he's absolutely correct on is the shape of
hummingbird territorial
> displays. Finally, a general use source that correctly
describes
> Rufous displays properly.
>
> narendra bhagwat wrote:
> >
> > Hi Tweets,
> > Today (10/22/00) I saw this male Anna's courtship
display at montlake fill.
> > I knew that this 'J' shaped display is fast, but never
imagined that it's so
> > fast that I can't even see it clearly. He was doing it
right above my head.
> > He was going very high up, hovering for few seconds and
then diving very
> > fast in a 'J' shape. It was so fast that I was able to
see him only at the
> > end. He repeated that at least 10 times. As he completes
the dive there was
> > a very high pitch buzz also. There was one more
hummingbird, but I'm not
> > sure weather female or not! This male was there from
11.00 am to 4.00pm.
> >
>
>
> --
> Mike Patterson Alas, to wear the mantle of
Galileo,
> Astoria, OR it is not enough to be
persecuted
> celata at pacifier.com by an unkind establishment,
> you must also be right.
> ---Ro
bert Park
> http://www.pacifier.com/~mpatters/bird/bird.html
>