White-tailed deer (Odocoileus virginianus)
were reported to be quite abundant when white
settlers arrived in Iowa in the early 1800's.
Although the clearing and cultivating of land
for agriculture may have initially improved the
suitability of the landscape for deer,
uncontrolled exploitation for food and hides
rapidly reduced deer numbers. By 1880 deer were
rarely sighted in much of the state and in 1898
the deer season was legally closed. By this time
deer had been virtually eliminated from all
parts of the state.
Reestablishment of Deer
Reestablishment of deer into the state can be
traced to escapes and releases from captive
herds and translocation and natural immigration
from deer herds in surrounding states. A
conservative estimate of the population in 1936
placed statewide numbers at between 500 and 700
animals. This small herd grew steadily. By 1950
deer were reported in most counties and the
statewide estimate topped 10,000. Concentrations
in some areas were beginning to cause problems
by damaging agricultural crops. In response to
these problems the first modern deer season was
held in December of 1953 and 4,000 deer were
killed. Currently, the deer herd is estimated to
be about 200,000 after the hunting season, and
harvests have approached 100,000 in recent
years.
Habitat
Although deer are normally associated with
forested areas, deer will utilize many different
types of habitat as long as the area provides
adequate cover. Examples of these types of areas
include brushy draws and fencelines, marshes,
and grassy areas like those provided by the
federal Conservation Reserve Program (CRP).
Standing corn also provides ideal habitat for
part of the year since it provides food, cover
and easy travel lanes. Deer utilize almost all
plants for food at one time or another during
the year. Deer feeding habits can best be
described as being erratically selective as deer
will sample many plants while feeding but often
utilize a single source of food for the majority
of their diet.
Deer Do Well in Iowa
The white-tail's ability to thrive in Iowa is
likely the result of an abundant, reliable food
source and a winter climate where snow depths
rarely exceed 12" for a prolonged length of
time. These factors combine to allow deer to
come through the "winter bottleneck" in
excellent condition. The excellent nutrition
also enables deer to have high reproductive
rates. Many deer in Iowa have a single fawn
their first year and 2 fawns each subsequent
year. Deer in the wild can probably maintain
these high reproductive rates until they are 10
years old. Past research in Iowa has found that
8 to 12% of adult does have 3 fawns.
Another reason that deer do so well in Iowa
is that they are very mobile. Although many deer
stay near the area where they were born, a
significant number leave and travel to new areas
before establishing a core area. These core
areas may change seasonally with deer shifting
between wintering areas and breeding areas.
These movements allow deer to fill voids left
open due to deaths and easily pioneer into new
areas when habitat is suitable. High rates of
movement occur during 2 periods of the year. The
first is in the spring when deer move to their
fawning areas. Many of last years fawns are
forced to find areas of their own at this time.
The second period is in the fall during the
breeding season. The breeding season begins in
mid-October and runs through mid-January,
although the peak of activity occurs during the
first 3 weeks of November.
Careful management of deer populations by man
has also played a crucial role in allowing deer
numbers to return to the levels enjoyed today.
Management consists of carefully regulating the
harvest since hunting provides the only major
source of mortality for deer today. Unchecked,
Iowa's deer herd could grow at a rate of 20% to
40% each year. At this rate, deer numbers would
double in as few as 3 years. With Iowa's
abundant agricultual crops providing food,
densities could potentially reach 100 or more
deer per square mile before natural regulatory
mechanisms would begin to affect deer health and
slow the rate of growth. Deer numbers this high
would cause economic hardship to Iowa's
landowners as well as alter the natural
vegetative community. Maintaining a deer
population in balance with the wants and needs
of the people in the state is a difficult task,
but hunting is the only viable management option
to achieve this goal.
For more information, contact the
Iowa Dept. of Natural Resources. |