Nature Notes for December 9, 2011
Just when local birders were despairing about the dearth of
interesting or unusual birds in the area, some turned up. In the last week of
November, at least five Snowy Owls were reported from Presqu’ile. These were
quickly followed by reports from Port Hope harbour, Cobourg harbour and Wicklow
beach.
The Ontario Field Ornithologists’ listserv is reporting
Snowies from all over southern Ontario.
On December 6, there was a large, dark Snowy Owl on
the end of the west jetty on the Port Hope lakefront. The previous Sunday, there was a
different one - much smaller and whiter - on the roof of a building just east
of the Port Hope water treatment plant.
As with most raptors, female Snowy Owls are larger than
males. As well, females are streaked with many dark bars. Adult males are
completely white, although young males may have some faint barring.
When there is snow on the ground, these birds can be very
difficult to see. Sometimes they look like a large lump of dirty snow. It’s not
until they turn their heads to show their yellow eyes that they are recognized
as a bird.
The white coloration is very good camouflage for a bird that
nests in the Arctic tundra.
Their primary prey in the Arctic is lemmings. When the
lemming population plummets, which it does on about a 4 year cycle, the owls
are forced to leave the north in search of food. That’s when they turn up in our
area.
In southern Ontario, there are no lemmings, so the owls
switch to other food: mice, voles, rats, rabbits, smaller birds – essentially
anything they can catch.
The breeding grounds are far enough north that, in summer, there
is almost 24 hours of daylight. Therefore, it is not unusual to see these owls
active during the day. If they winter in the Arctic, they also spend part of
the year when they have to be active in darkness.
This species is one of many Arctic nesting birds that have a
circumpolar range. That is, they occur in the north of Europe and Asia as well
as North America.
Locally, they are often found along the waterfront. Perhaps
those open, windy sites look to the birds like the tundra. They can be found in
any open site and are often found in agricultural fields. They have also been
found perched on utility poles, fence posts, barns and silos. In town, I’ve
seen them perched on top of buildings. Several years ago, on the last irruption
of Snowy Owls, I found one sheltering alongside the air conditioning unit atop
the condos at Cobourg harbour. A number of years ago, I awoke to one perched on
the chimney of the house of my back fence neighbour.
To date, this seems to be a good year for Snowy Owls in the
south. It’s worth really looking at that lump of snow. It might turn out to be
one of the visiting owls.
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The annual Christmas Bird Counts will be held before the
next column appears. Port Hope-Cobourg’s count is on Saturday, December 17 and
Presqu’ile-Brighton’s on Sunday, December 18.
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