|
Spring
2003
Skunks Dance with Death
 by
Stan Gehrt
A deadly serious, if quiet, struggle
for survival by one of our most recognized animals, the
striped skunk (Mephitis mephitis), played out underneath
the snow this past winter. As part of a project supported
by the Illinois Department of Natural Resources and the
Max McGraw Wildlife Foundation, my technicians and I have
been studying the ecology of striped skunks in northeastern
Illinois since 1998. We focused in part on discovering what
limits skunk populations.
Each spring and autumn, our team has
"live-captured" and tagged skunks throughout Chicago
Wilderness. Believe it or not, the most successful technique
is to capture skunks by hand. We survey the study areas
at night with spotlights, and when the white stripe is spotted,
we chase the skunk with nets. The ensuing dance between
skunk and technician, both jockeying for position —
one to pounce with a net, the other to eject a spray from
its posterior — can be quite entertaining, and usually
culminates with a telltale odor. While regular people avoid
that famous skunk spray at all costs, we associate it with
the sweet smell of success. After many changes of clothes,
we have radio collared more than 100 individuals, allowing
us to track the movements of each.
When winter arrives, the previously
antisocial skunks begin sharing ground burrows during the
day. As the ground freezes, skunks settle in dens together
for the winter, emerging only to relieve themselves and
perhaps check the weather. As many as nine skunks have shared
a den.
We have found that most skunks survive
through the warm seasons, with little pressure from predators
and surprisingly few deaths by vehicles. However, in a typical
year, fewer than half of the skunks that enter winter dens
survive to the following spring. Those that do survive have
often lost as much as half their autumn weight. Skunks are
not capable of true hibernation — their metabolic processes
continue during these long inactive periods, and their energetic
demands exact a toll. Communal denning may be a strategy
by skunks to conserve body heat.
Nearly all skunks suffer from physical
maladies such as parasites and viral infections. Generally,
the skunk tolerates these problems during the year. However,
during the winter, as the skunk's physical condition deteriorates,
so does its immune system, and the infections become fatal.
Consequently, few skunks live to two years of age. The oldest
skunk we have documented was a five-year-old female.
Currently, we are tracking young skunks
as they leave their birth dens in an effort to determine
how individuals are related. We also are examining other
ways in which diseases affect skunks. There are still some
secrets under the snow that remain to be discovered.
Max
McGraw Wildlife Foundation
Illinois
Department of Natural Resources
|
