Tweets:

Inspired by the continuing thread on hunting by crows, and curiosity about
whether my magpie observation was nest defense or attempted predation, I
finally thought to consult _The American Crow and the Common Raven_, by
Lawrence Kilham. Though his observations were primarily of crows, I presume
that some behaviors would correspond to those of magpies and other corvids
as well.

He describes several types of interaction of crows with mammals. Crows were
seen to rob squirrels of food and tweak the tails of other mammals,
apparently at times to rob them. As regards potential predation, he writes:

"_Attacks on Young or Weakened Mammals_. Crow behavior can be difficult to
interpret. ... Attacks can be a way of testing whether the prey is feeble
or incapacitated enough to subdue." His reports include watching crows
attack deer fawns and pigs.

In Chapter 8, "Defense of Nests and Other Interspecific Interactions," he
writes: "_Squirrels_. Gray squirrels were very prevalent and a constant
threat to crows' nests. Two crows flew at a squirrel silently on March 27,
one or the other swooping when the squirrel ran over the ground or exposed
itself on a tree trunk. ... Crows were especially concerned if a squirrel
climbing an adjacent tree reached the level of a nest. Female B was on her
nest when a squirrel climbed to her level. She spent the next five minutes
driving the squirrel from branch to branch, aided by a second crow. Both
crows were silent. ... The most prolonged attack witnessed was on April 9,
1985, six days before the two nestlings of the A3 crows left their nest.
Two crows started attacking when the fox squirrel was 15 meters from the
nest tree. The crows continued swooping silently as the squirrel moved
across 150 meters of pasture to another oak. Here the crows worked for some
minutes to get the squirrel back to the ground, then drove it across 50
meters more of pasture."

My conclusion is to agree with his statement that crow behavior is
difficult to interpret accurately. (Personally, I sometimes wonder if they
could also have a capacity for amusement!) As for the magpies, apparently
their lack of vocalization did not necessarily rule out nest defense and
indicate predatory intent instead. I don't know what the heck they were
really doing. But it doesn't detract from the fascination in watching them
and *trying* to figure it out :)

Watching crows "doing their thing" in P.T. --

Janet Hardin
Port Townsend, WA
wins at olympus.net