Tom Cotner:

>After a series of piercing
>introductory cries that echoed down the canyon, the eagles suddenly locked
>talons and plummeted more than 2000 feet!! before disengaging only about
>100-200 feet above the ground.
>This immediately precipitated a rash of speculation on whether these were
>potential) mates or possibly rivals and on the "why" of it, but I still
>don't really know. Anyone out there care to speculate if this is
>"courtship" behavior?

"Talon grasping and cartwheeling are not separate displays but are
among the possible consequences of territorial disputes. Such
interactions apparently occur when a single bird enters
the domain of a breeding pair; an owner dives at the interloper,
who flips over with feet extended upward, and the two catch or lock
talons and tumble or cartwheel toward the earth until they disengage...

Two dead eagles were found in Scotland with talons still locked;
apparently they had fought to the death over territory (cite given)"

Handbook of American Birds, V. 5.

Cool? Regarding the latter, I wonder if they really fought to the
death or just didn't notice the ground coming up at them? :)

>The eagles worked as a team, with one eagle harrassing
>the bear while the other eagle pulled the smallest caribou piece farther
>away from the carcass.

Two eagles - a pair - feeding together doesn't surprise me (and I loved
your description of this event). The threesome mentioned by Bent (or
did I mistunderstand?) did though.

However, book to the rescue once again. Tandem hunting by mated
pairs is fairly common, particularly of jackrabbits (one flusher,
one pouncer). And by more eagles, while uncommon, isn't entirely
unheard of according to the Handbook's entry. Unfortunately the
first offhand example mentioned seems to be Bent's example so as
proof it's pretty self-referential! There is, apparently, a well-documented
case of three eagles killing a winter-weakened pronghorn in 1908.

Apparently there's no evidence of juvie-only cooperative hunting, so
sounds like "the fam" engaging in a little kids-helping-the-folks-with-
chores kinda thing.

Other interesting feeding stuff since I've got the book out:

"Mistakes:

Young birds, especially, attack prey they can't kill. <then
gives an example of a young eagle hanging on to the back of
a steer for 300 meters with no success, then flying off to
try again with another>.

Porcupines - often a fatal mistake, though some in the east
have been observed doing so successfully <gives examples of
emaciated dead eagles quilled like a pincushion>.

<And a classic, one I performed on my very first trip as a leader,
falling for a duck decoy>:

In Coloado, a golden alighted at the water's edge and waded
<WADED?!?> toward a pintail decoy. In Texas two pintail decoys
were attacked and showed talon damage (both with cites)"



- Don Baccus, Portland OR <donb at rational.com>