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Angus Gavin was a fur trader at the Perry River post of the Hudson's
Bay Company on the edge of the Arctic Ocean. White foxes were the
chief fur brought in, and the Eskimos were the trappers. Sometimes it
was necessary to advance credit to an Eskimo, against the expectation
of a coming season's catch out of which the advance was to be repaid.
Gavin, who was a keen naturalist as well as trader, writes, "I used my
observation on Snowy Owl abundance to govern extension of credit...."
When snowy owls were abundant he could extend liberal credit to the
Eskimo with every assurance the white-fox catch would be good and that
the Eskimo would be able to liquidate his debt. When snowy owls were
scarce little credit would be extended, for the white-fox catch would
be small.
In general we've accepted the value of birds to man, and are
appreciative of the complicated web of life in which one animal affects
many others. But this use of snowy-owl abundance as a guide in granting
credit strikes me as novel. Actually, of course, it is quite sound, for
it uses one part of the chain that links such diverse items as owls,
lemmings, foxes, Eskimo, fur trader, and finally of course milady in
her white-fox furs.
LEMMINGS IMPORTANT First of the factors involved is, of course, the
vegetation; the grasses, herbs, and tiny dwarf shrubs of the Arctic
barrens. The next are the lemmings, mouselike creatures of the Far
North that eat the vegetation. They are the first step in turning
grass into flesh and fur and feathers. One of the striking facts of
lemming biology is the fluctuation in their numbers. Some years they
swarm, lemmings are everywhere, and in places they erupt in vast
emigration, the tundra and the sea ice being covered with masses of
moving lemmings. We know this best from the accounts written about the
lemmings of Norway, but the same thing occurs in the American Arctic.
At other times they're scarce and it is difficult to find even one.
Strangely there's a periodicity in this, and periods of abundance and
scarcity tend to recur every four years. What happens or what causes it
we don't know.
The Arctic fox, staple fur bearer of the Far North, and the snowy owl
both prey on lemmings. Lemmings are so important to them that when
lemmings are abundant the foxes and the owls prosper and multiply; when
the lemmings are scarce the foxes and the owls starve or migrate, in
any case where there are few lemmings there are few foxes or owls.
Thus we see how it is that an abundance of snowy owls can indicate
that the Eskimo will make a good fox catch and the trader will do good
business.