The American Midland Naturalist 177(2):200-210. 2017
doi: http://dx.doi.org/10.1674/0003-0031-177.2.200Diets of Fishers (Pekania pennanti)
and Evidence of Intraspecific
Consumption in Pennsylvania
Received: December 17, 2016;
Abstract
The fisher (Pekania pennanti) is a forest-dwelling mesocarnivore native to northern North America. The species had been extirpated from many southern parts of its historic range, but several states have implemented fisher re-introduction programs over the past 40 y. While many studies have previously examined fisher diet, most occurred in northern and western portions of the species' range where mixed and coniferous forests are the dominate cover types. We examined fisher diet, in a re-introduced population in the central Appalachian Mountains where deciduous forests were the dominate cover type. We collected 91 fisher carcasses from 2002–2014 and examined their stomach contents. We detected mammalian and avian prey in 82.6% and 10.9% of stomachs, respectively. Fishers we sampled consumed a variety of plant materials (n = 11) and prey items (n = 30 spp.). Diet composition of males and females overlapped considerably (O = 0.87).
Our most noteworthy and novel finding was the presence of fisher remains in 11 (12%) stomachs. We suggest here that rapid population growth of Pennsylvania fishers may have resulted in aggressive behaviors underlying our observations of interspecific consumption. Future research that examines the cause for intraspecific consumption in this central Appalachian fisher population would be a worthy endeavor.
Our most noteworthy and novel finding was the presence of fisher remains in 11 (12%) stomachs. We suggest here that rapid population growth of Pennsylvania fishers may have resulted in aggressive behaviors underlying our observations of interspecific consumption. Future research that examines the cause for intraspecific consumption in this central Appalachian fisher population would be a worthy endeavor.
Author Affiliations
1 Corresponding author present address: Cornell University, Natural Resources, 111E Fernow Hall, 226 Mann Dr., Ithaca, New York 14853: e-mail: djm462@cornell.
Darin J. McNeil, JR.1
Department of Biology, Indiana University of Pennsylvania, Weyandt Hall, Room 114, 975 Oakland Avenue, Indiana 15701
Courtney A. Nicks
Department of Biology, Indiana University of Pennsylvania, Weyandt Hall, Room 114, 975 Oakland Avenue, Indiana 15701
Jennifer C. Wester2
Department of Biology, Indiana University of Pennsylvania, Weyandt Hall, Room 114, 975 Oakland Avenue, Indiana 15701
Jeffery L. Larkin
Department of Biology, Indiana University of Pennsylvania, Weyandt Hall, Room 114, 975 Oakland Avenue, Indiana 15701
Mathew J. Lovallo
Pennsylvania Game Commission, 2001 Elmerton Avenue, Harrisburg 17110
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STATUS AND MANAGEMENT
OF FISHER
(MARTES PENNANTI) IN
PENNSYLVANIA
2008-2017
EXECUTIVE SUMMARY
The fisher (Martes pennanti) is a mid-sized terrestrial and arboreal carnivore and is the
second largest mustelid currently found in Pennsylvania’s forest ecosystems. Historic
accounts suggest that, prior to colonial development, fisher were once found throughout
forested regions in Pennsylvania. Subsequent wide-scale deforestation and dramatic
alterations in forest structure and prey resources resulted in fisher population declines.
Due to limited accounts of fisher during the last century, it is difficult to estimate the
exact timing or progression of fisher extirpation in PA, but the last confirmed report,
prior to the recent population recovery, was in Mifflin Co. in 1923.
Fisher populations are currently established and are expanding throughout much of
southwestern, central, and northern Pennsylvania. This “present day” fisher population is
the direct result of a large-scale reintroduction program within Pennsylvania and natural
expansion from reintroduced populations in West Virginia and New York. The
conservation and management of Pennsylvania's fisher population is of interest to
hunters, trappers, and non-consumptive users alike. The development of a comprehensive
fisher conservation and management plan is necessitated and prioritized by growing
public interest and concerns about fisher population expansion in Pennsylvania. The
foundation of Pennsylvania’s fisher management approach lies in this plan’s mission
statement:
“Promote stability and continued expansion of fisher populations within suitable habitats
throughout the Commonwealth and minimize human conflicts and impacts on other
wildlife populations”.
The fisher management plan provides a comprehensive and current summary of fisher
biology, historic and current status in Pennsylvania, population recovery, economic
significance, public interest, and regional population and harvest management
approaches. The plan also provides supporting objectives and strategies to achieve five
species-specific goals related to population monitoring, habitat assessment, population
enhancement, and development and implementation of a harvest management program.
To assist with implementation planning, an appendix is included which provides target
dates for specific project objectives. Successful implementation of this plan will require
further acquisition and reallocation of resources within the agency and from outside
sources. The feasibility of implementing a fisher harvest season is addressed using a
conceptual fisher management model and a wildlife management unit-based decision
matrix. The decision matrix is designed to provide guidance for harvest management
decisions such as the timing, areas, and methodologies associated with a fisher harvest
season
MORTALITY
Due to the fishers’ size, strength, and arboreal abilities, they are rarely preyed upon by
other forest carnivores, but predation has been reported by mountain lion, coyote,
wolverine, golden eagle, wolves, and lynx (Krohn et al. 1994, Douglas and Strickland
1987, Roy 1991). Intraspecific strife has been noted among adult males and litter-mates
and intraspecific mortality has been documented in captive populations.
Due to the fishers’ size, strength, and arboreal abilities, they are rarely preyed upon by
other forest carnivores, but predation has been reported by mountain lion, coyote,
wolverine, golden eagle, wolves, and lynx (Krohn et al. 1994, Douglas and Strickland
1987, Roy 1991). Intraspecific strife has been noted among adult males and litter-mates
and intraspecific mortality has been documented in captive populations.
Regulated trapping is a significant source of mortality within many fisher populations.
Fishers are relatively easy to capture and males are generally more susceptible to harvest
than are females due to increased mobility and larger home ranges. It is unknown
whether human-related harvest mortality is compensatory or additive (Douglas and
Strickland 1987).
Habitat Selection
In the most general sense, fisher occupy mesic, confer or mixed conifer forest with
abundant physical structure (i.e., downed woody debris) on the forest floor. Lancaster et
al. (2008) found that fisher abundance was positively related to the proportion of
landscapes containing forest cover. Fisher are generally believed to avoid areas lacking
overhead cover but degree to which fisher will tolerate varying levels of forest
fragmentation has not been well studied. Significant structure on or near the forest floor
is most important during winter periods as it may provide subnivian spaces in which to
forage and rest (Buskirk and Ruggerio 1994).
Although late successional forest appears to be a significant requirement in some western
populations, this does not seem to be the case in the eastern U.S., where fisher occupy
deciduous forest stands at varying successional stages. Varying silvicultural practices,
combined with extensive gypsy moth-related or other pathogen-caused forest mortality,
may provide adequate structure on or near the forest floor to support eastern fisher
populations.
Most studies of habitat selection have been conducted to evaluate stand use and microsite
selection. These studies have generally concluded that fisher prefer mid–to-late
succession conifer stands, but will inhabit partial or entirely deciduous stands as well
(Powell et al. 2003). Powell (1994 for resting sites than foraging areas. Conversely, Weir and Harestad (1997) found no apparent landscape-level trends in habitat selection. Seasonal patterns of habitat selection
are not well documented but selection is thought to be less apparent during summer than
during winter (Kelly 1977). Fisher avoid habitats associated with deep soft snow during
winter because of their relatively heavy foot loadings (Krohn et al. 1995). In general,
fisher select the most structurally complex forest stands available, particularly at or near
the forest floor.
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