Pennsylvania Game News - July 2016 - 14

carnivores - everything from skunks to
opossums - were second at 23 percent.
Fishers also prey on eggs, fruit, frogs and
black snakes, even silver-haired bats and
Allegheny woodrats. Deer also comprised
a significant chunk of the fisher's diet,
but most likely is the result of roadkill
consumption.
Squirrels, porcupines, cottontails, voles
and deer mice made up about 60 percent
of the diet of the fishers examined. All are
abundantly available in Penn's Woods,
especially squirrels.
Squirrels, given their relative gregariousness, surely have been important to
fishers dispersing into Pennsylvania's
remaining unoccupied fisher range. Readily available throughout much of Pennsylvania, a squirrel seems about the perfect
size for a fisher meal. Its pound of meat
isn't exactly the tenderized smorgasbord
a road-killed deer provides, but it's still
substantial and available for take-out.
The decline of squirrel hunting in
Pennsylvania might have helped make
squirrels a staple in fisher diets. Back in
the early 1980s, the Commonwealth's
squirrel harvest was an amazing 3 million
(700,000 squirrel hunters). Today, the
harvest is about a half-million (120,000
squirrel hunters), leaving a generous
annual yield of squirrels in the woods.
It's no wonder fishers are capitalizing
on a renewable resource that half a million
hunters or so abandoned over the last 25
years. It's a resourcefulness you can't help
but to admire.
Although literature documents fishers exhibiting preference for evergreen
stands, IUP's fieldwork showed they
are very particular about using roomy
deciduous-tree cavities for rest sites and
maternity dens, regardless of the forest's
composition. If woody wreckage - fallen
trees and branches, rotting trunks - is
14

located close by, the area immediately
seemed more appealing to fishers.
Just like working a canopy, fishers
seem to prefer a forest floor cluttered with
debris through which to slink. The spatial
cover provides for prey, but also accommodates a predator. Consequently, the
new growth and prey cover provided by
a 10-year-old chop-off might have just as
much appeal to a hunting fisher as a stand
of acorn-rich oaks.
"Fishers are certainly opportunistic,"
Lovallo noted. "As a general carnivore,
they feed on a suite of mammalian prey
and supplement their diet through the
seasonal consumption of birds, reptiles,
plant materials, even fungi."
But fishers aren't sitting alone atop the
food chain pyramid.
"They compete directly with bobcats and coyotes, particularly when
scavenging for deer remains, an important food component for all predators,"
Lovallo explained. "Still, fishers have
some advantage over other forest predators, because they can forage effectively in
the treetops, as well as on the forest floor."
No other predator really possesses that
versatility in Pennsylvania. Bears and
bobcats - even gray foxes - can climb.
But they cannot negotiate a canopy like a
fisher. That advantage matters a lot when
assessing the fisher's population growth
and emergence across the state over the
past two decades.
Lovallo pointed out that the fisher's
ascension might cause problems for bobcats, another species that has flourished
in the Commonwealth in recent decades.
There's some evidence, Lovallo said, that
fishers also might directly prey on juvenile
bobcats. So far, though, there's been no
evidence in Pennsylvania to support that
concern.
Another interesting find in the bellies

Table of Contents for the Digital Edition of Pennsylvania Game News - July 2016