I'd like to thank everyone who participated in this edifying discussion
about Snowy Owl hunting hours. It would be nice if the guide books would
give the broader picture. But, barring that, at least we have some
perspective. And, the posting of the old publications about Snowys was
an added bonus.
Ardith Bondi
On 12/4/13 8:49 PM, Angus Wilson wrote:
As others have said already, being a high-arctic breeder Snowy Owls
really have no choice but to hunt in daylight because there is little or
no night during the summer. This, I would guess, is what the textbooks
are referring to. The opposite will be true during the winter for the
many birds that stay north, when the night is long. Also the owls will
have the prey to themselves when strictly diurnal competitors such as
Rough-legged Hawk and Golden Eagle are roosting. So to persist in the
far north the species must be quite flexible relative to other owls and
this would come in handy when birds irrupt southward.
Speaking from a coastal perspective, I've never seen a wintering Snowy
actively hunting during the day time. They certainly move around,
occasionally spar with others when present, dodge attacks from
Short-eared Owls or hawks and are generally vigilant but don't seem to
be hunting per se. I've routinely seen them become much more active at
dusk, presumably in preparation for a night of hunting. It would be
interesting to hear if this rest up during the day and hunt by night
holds true for birds wintering on farmland where they target different
prey from those on the coast.
Many will remember the Snowy Owl that frequented Piermont Pier (Rockland
Co.) in Februrary 2007. This bird dined on Ruddy Ducks snatched from the
sheltered bay, bringing them back to a perch where the pile of discarded
heads and feet attracted a most splendid adult Ivory Gull. My
recollection was that the owl fed mostly at night but maybe someone can
confirm or refute this. A priori, it would seem a lot easier for the owl
to swoop down on roosting ducks (and as we've heard roosting gulls)
under the cover of darkness when it has the visual advantage. Phil
Jeffrey has posted pictures (albeit gory ones) of the polishing off a
stiff tail.
http://philjeffrey.net/piermont2.html
Bottom line, individual Snowy Owls can probably adapt their
feeding/roosting cycles to fit the available prey. I imagine they also
hunt less and roost more if food is easy to acquire during optimal
periods. With so many owls around this year, it would interesting to
learn from field observers what the current birds (largely immatures by
the fact that most are very heavily barred) are feeding on and when they
do so. One more reason to view from a distance and let them to do their
thing.
Angus Wilson
New York City
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