Don and Sandi McVay wrote:

..... The crows on Orcas and in Seattle have been exhibiting a behavior that
we have only recently observed. It looks like the equivalent of the
"spy-hopping" behavior for which Orcas are famous, except of course this is
aerial "spy hopping".

The crows we observed at different locations and different times fly
vertically into the air until they are several meters above the trees and
then glide downward at a steep angle until they are about mid-tree level
where they again fly upwards vertically and repeat the downward glide
completing an approximation of a figure 8. They do this behavior several
times consecutively.

Several birds may do this in unison or single birds do this behavior while
others sit in nearby branches watching. Since many crows are nesting right
now, we wonder if this has something to do with breeding behavior or nest
protection, although no nests were obvious where this behavior was taking
place. ANY IDEAS?
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Hi Don & Sandi -

The behavior that you're describing sounds a lot like what I've seen when
crows are harrassing predators.

Next time you see the crows doing this, put your glasses into the tree and
see if you can't see an Eagle, Red-tailed Hawk, or Horned Owl - who is
probably trying her/his best to ignore the crows and continue on with a day
of hunting....

Jon's best guess Anderson
Olympia, Washington
festuca at olywa.net