On Wed, 6 Nov 1996, Katherine A. Weil wrote:

> Dave Eshbaugh at Portland Audubon told me they received a dead SNOWY OWL
> yesterday--was hit by a car out by the airport. Apparently the bird WAS
> mobbed by crows, driving it towards the roadway (no pun intended). I also
> heard that someone got the whole thing on videotape. Email Dave for more
> detail at: deshbaugh at audubon-pdx.com
>

I tend to side with Roger Hoffman's observations of crow-owl interactions:
that crows mob moving owls vigorously, but will fairly quickly quit once
the owl has been stationary for a while, once "the neighborhood has been
alerted," perhaps. In my experience, a mob of crows almost never directly
cause an owl to flush - quite the contrary, owls are more likely to hunker
down and wait for the crows to lose interest when being mobbed. If a Great
Horned were mobbed while perching in a spot out in the open, it would not
surprise me if it responded by seeking a more sheltered spot in an
evergreen. In that sense, I guess you could say the crows were driving
the owl to cover, but that's the exception rather than the rule.

Indirectly, crows can cause an owl to flush, by attracting a "bigger
predator." I have been that bigger predator many times. But the idea
that crows drive owls hither and yon is not really in line with what I've
observed.

Incidentally, there is a large, if scattered, literature on why small
birds might mob larger ones that might eat them. At first glance, it
doesn't seem to make evolutionary sense, since the small bird probably
does increase its chances of being eaten, no? Berndt Heinrich's book "One
Man's Owl" does a good job of discussing the various possible explanations
for this paradoxical behavior.

So, back on topic, in the incident above, I don't question that the Snowy
Owl was being chased by crows before it was hit, but I would need some
convincing before I accepted that the crows (as opposed to the cameraman,
for example, or just a whim of the owl) had caused the owl to fly into the
path of the car.

Chris Hill
Everett, WA
cehill at u.washington.edu