Illinois Natural History Survey Reports

              1
I LLINOIS
NATURAL
HI STORY
S U R V E Y R e p o r t s
May/
June 1999
No. 357
I N S I D E
Ecological Monitoring
for Illinois Soils
2
Development of an
Individual-based Model
to Evaluate Growth and
Survival of Walleye
3
The Role of Fire in
Maintaining Plant
Diversity in Oak Wood-land
Communities
4
Species Spotlight:
Orangethroat Darter
6
The Naturalist's
Apprentice:
So Many Fishes! How
Can You Tell Them
Apart?
7
Continued on back page
Deer in the Suburbs of Chicago
The management of overabun-dant
deer populations in suburban
areas continues to be one of the
most immediate and frustrating
problems facing conservation
and wildlife profession-als
nationwide. As rapid
development encroaches
on the remaining open
landscapes surrounding
most metropolitan areas,
wildlife is forced into
ever-shrinking islands
in a sea of development.
This concentration of
wildlife into smaller and
smaller areas causes intra-specifi
c competition for
the remaining available
resources. In particular,
overabundant white-tailed
deer can cause severe
impacts to ecosystems
through excessive browsing, and
they also pose threats to public
safety through deer-vehicle colli-sions
and the potential spread of
wildlife-borne diseases.
The solutions to managing
overabundant deer in suburban
settings are often controversial,
posing new challenges to manag-ers.
The traditional method of
population control, recreational
hunting, is unacceptable to ur-banites.
Additionally, despite the
proliferation of literature pub-lished
about deer, little research
has focused on the biology of
this species in its newly exploited
suburban environment. Basic life
history information is crucial to
managers attempting to reduce
and then maintain ecologically
responsible suburban deer popula-tions
using alternative manage-ment
techniques.
With funding from the Forest
Preserve Districts of Cook and
DuPage counties, Cook County
Animal Control, and Chicago
Wilderness, we are developing a
model to predict population trends
in suburban deer and documenting
the recovery of native plant com-munities
as deer populations are
reduced.
Work to document life history
information for deer from the For-est
Preserve Districts of Cook and
DuPage counties began in winter
1995. More than 130 deer have
since been captured and radio-collared.
Deer were monitored
for survival and radio-tracked to
document movements within the
suburbs of Chicago. Additionally,
reproductive information was
collected from more than 4,000
deer removed from forest pre-serves
during culling operations
designed to reduce overabundant
populations. Col-lection
of vegetation
data began in Du-
Page County forest
preserves in 1991,
two years prior to the
initiation of deer cull-ing
operations. This
summer will repre-sent
the ninth year for
collection of this im-portant
information.
Life history in-formation
to support
our model includes
classic deer biology
as well as unique be-haviors
for suburban
deer. In general, suburban does
are homebodies living out their
lives in the same general area as
their mothers. Bucks, however,
are gregarious, often dispers-ing
during their second summer.
Suburban deer often existing at
extremely high densities (>150
deer/mile2) continue to have high
fecundity (>1.6 offspring per
adult doe) even when understory
vegetation is severely depleted.
Populations at these extreme
densities are checked somewhat
by reduced breeding by younger
does and by higher fawn mortal-ity.
Overall survival for adults is
greater than 80% annually, which
Fawn in suburban Chicago.
Photo by Dwayne Etter, University of Illinois
intra-
Photo by Dwayne Etter, University of Illinois