JF Griffin - Index

JF Griffin - magazine - Index

Using
Distance
Sampling
to Estimate
the Number
of Deer
Although the technique is easy, it is
also time-consuming. Frequently, wildlife
personnel drive the survey route multiple
times over the course of several evenings
to obtain the proper sample size.
The number of miles driven, the number of
deer seen and the distances from the observer
to the deer are entered into Distance 5.0, a
computer program which calculates the deer
population estimate of the survey area.
By Susan Predl, Principal Biologist
Distance sampling is a survey technique used by wildlife
biologists to estimate the number of deer in an area. At
night, roads are driven through the survey area maintaining
a speed of 10 – 12 miles per hour. Observers use spotlights
to find and count deer, then measure the distance between
observer and deer with a laser range finder.
There is a decreasing
probability of seeing deer as they
are further from the road. To
obtain a valid population estimate,
at least 50 groups of deer must be
observed.
New Jersey Division of
Fish and Wildlife has used
this technique to estimate
deer populations in several
areas. Locations include
deer browse study sites,
such High Point State Park,
Sussex County; suburban
municipalities where
Community Based Deer
Management programs were
in place such as Watchung
Borough, Somerset County
and in county parks where
deer culls have occurred,
such as South Mountain
Reservation, Essex County.
34 | New Jersey Fish & Wildlife Digest Buy your license or permit online at August 2008
2008 Hunting and Trapping Issue www.NJFishandWildlife.com