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-------- Original Message --------
Subject: [Taxacom] Hypothesis about another irruption of snowy owls into
U.S.
Date: Sat, 14 Dec 2013 01:56:47 +0000
From: Ken Kinman <kinman@hotmail.com>
To: taxacom@mailman.nhm.ku.edu <taxacom@mailman.nhm.ku.edu>
Dear All,
Just two years after the big snowy owl irruption of 2011-2012,
another one is now making news across the eastern U.S. (even here in
Kansas). Anyway, it is my increasing suspicion that these irruptions of
snowy owls into the United States might become quite frequent. Although
much is said about their population numbers depending on the populations
of their prey (especially lemmings), not much is said about the effects
of predation on snowy owls themselves (especially the chicks).
One of the few predators of snowy owl chicks which the parents
are unable to chase off is the polar bear. As polar bear numbers
decrease, they will eat less snowy owl chicks, and snowy owl populations
can quickly increase in years when there is plenty for them to eat. But
then the lemming population will tend to crash even more quickly, and
the excess snowy owls must then fly south for food.
Anyway, with fewer polar bears to keep the snowy owl population
in check, I think the population booms and busts of both snowy owls and
lemmings will become more frequent and severe. Some have claimed that
polar bear populations are actually increasing, but I suspect that the
bears are just invading human settlements more often in search of easy
food in garbage dumps. Scavenging polar bears could be increasing, while
the total population is decreasing. The whole ecosystem is out of
balance.
Thus snowy owl irruptions into the United States could become
larger and more frequent. Therefore, I don't think the more frequent
irruptions are as puzzling as some make it, if only they would look past
other hypotheses (weather patterns or lemming population fluctuations)
and look at decreased predation upon snowy owl nests as a primary factor.
---------------Ken Kinman
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