The brief life and times of
snowshoe hares
By NED ROZELL
March 10, 2009
Tuesday
Here on this March morning, in the forested floodplain of the
Tanana River, snow is falling with vigor. Even the paddle-feet
of snowshoe hares press several inches into the new fluff.
Knut Kielland wears metal-frame snowshoes as he zigzags through
alders and willows near the frozen river. He stops when he sees
a snowshoe hare, right where he expects it-inside a wire-screen
metal box.
The hare, which ventured into the live trap in pursuit of alfalfa
chunks and a carrot, wears a collar with a tiny transmitter the
size of a triple-A battery. Kielland, an ecologist at the University
of Alaska Fairbanks, and his colleague Karl Olson have captured
this animal before.
Knut Kielland of the
Institute of Arctic Biology at the University of Alaska Fairbanks
prepares to release a snowshoe hare from a live trap near the
Tanana River.
Photo by Ned Rozell.
Kielland coaxes the hare into a game bag, then weighs the three-pound,
snow-white creature, checks numbers on its ear tags, and releases
it into the forest. The hare then bounces away, seeming to disappear
into the winter world. But Kielland can find it anytime he wants,
using a binocular-size radio receiver and a handheld antenna
that resembles a TV antenna.
Kielland and Olson have fitted 50 transmitters onto the necks
of hares and often recover them again and again. Once a transmitter
was recovered from high in a spruce tree where a goshawk carried
its meal. Using a receiver and all of those transmitters, Kielland
is trying to find out the fate of the average hare. He wants
to answer a simple but elusive question: how long does a boreal
forest hare live in Alaska, and how does a population of hares
fluctuate?
"(With methods such as ear tags), you don't know whether
the hares dispersed out of your area or died," he said.
"This is an attempt to really find out what happens to them."
Biologists think hares probably live for about a year, with old-timers
reaching three or four, but there are few ways to judge that.
Kielland's study, which is the extension of a project he's been
working on in his backyard of the Tanana River for a decade,
should provide some answers.
The transmitters now carried by about 30 hares in the Bonanza
Creek Experimental Forest emit a steady beep when hares are on
the move. When one stops moving for about six hours, which means
it's probably dead, the beep rate doubles. Then, Kielland and
Olson turn on the receiver, unfold the antenna, and go on a search
for the collar. Not long ago, they found that a lynx they had
been tracking with a satellite collar had intersected the path
of a hare, the collar of which then started beeping rapidly.
"Our collared lynx ate our collared hare," Kielland
said.
Why study hares? The little creatures with the boom-and-bust
cycles (which are currently near a peak in the Tanana valley)
are food for just about every predator out there, from owls to
lynx to coyotes to red squirrels,
which hit the hares surprisingly hard just after young (leverets)
are born, researchers in the Yukon found.
Hares produce lots of offspring, dropping litters of as many
as five leverets up to three times each summer. That's a potential
15 little hares from one female, but hares disappear fast under
pressure from predators and
from starvation. Seven out of ten hares collared in June 2008
are no longer alive.
"They do bite the bullet in winter," Kielland said.
In a patch of the Interior he has studied, trapped, and hunted
in for many years, Kielland monitors the hares each year for
intense four-day periods in June, August, November, and March
to learn more about one of the most important little creatures
out there, a substantial meal for carnivores in the hungry country
of the boreal forest.
NOTE:
The granddaughter of Alva Wisdom,
a Seward man killed by a tsunami resulting from the 1964 earthquake,
wants to know if anyone out there remembers Alva and his wife
Mabel. If you do, send Ned Rozell [nrozell@gi.alaska.edu]
an e-mail.
This column is provided
as a public service by the Geophysical
Institute, University of Alaska Fairbanks, in cooperation
with the UAF research community.
Ned Rozell [nrozell@gi.alaska.edu]
is a science writer at the institute.
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