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Matt--
That's a good question I haven't thought about. I don't think cold
weather prompts unusual local arrivals of northern birds any more than
hot weather does the same for southern birds. They are adapted to the
weather extremes in their ranges. For example, we are probably not
seeing this invasion of snowy owls because it is too cold up north. The
important factor is food.
I don't think anyone can predict large incursions of birds based on
weather alone, unless the weather affects food sources. Back in the late
19th century, Ohio and neighboring states experienced a winter invasion
of thick-billed murres, which was thought to have been caused by a
failure in an important food source for this species: I wrote an article
for the Cardinal about this species, not seen here for many many years,
in the Winter 2003-4 Ohio Cardinal. It seems similar factors may have
been involved in the unprecedented (for humans at least) incursion of
razorbills last winter, which appeared in large numbers as far south as
Miami (see the new issue of North American Birds)! Many birders are
aware of the extreme variations in the numbers of winter finches each
winter, which seem to be influenced by varying seed crops in the
northern forests. These seem to be the best factors we humans can use to
predict occurrences so far ahead for birds of the north.
Extralimital occurrences happen for reasons we cannot always predict.
We had a royal tern here near Columbus three years ago, but no one had
any idea ahead of time that violent storms along the Gulf would sling
one up this way in 2011.
So my answer would be we can't tell, and isn't that part of the
intriguing mystery?
Shivering,
Bill
Bill … Can you also pontificate on what types of birds might be coming
down with the arctic weather we should be on the look out for?
Thanks!
Matt
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