MICHIGAN STATE UNIVERSITY
Scott R. Winterstein, Ph.D
Department of Fisheries and Wildlife
Michigan State University
East Lansing, Michigan
May 13, 1997
This report outlines the results of an efficacy test of Green Screen,
a product of Envirodyne, Inc. as a white-tailed deer repellent. The
field experiments were conducted by Eric Grinstern under the direction
of Dr. Glenn Dudderar (Associate Professor of Wildlife Biology, Department
of Fisheries and Wildlife, Michigan State University). All statistical
analyses were conducted by Dr. Scott R. Winterstein (Associate Professor
of Wildlife Biology, Department of Fisheries and Wildlife, Michigan
State University).
Field Trials
All field trials were conducted in an old field adjacent to a woodlot
on the Michigan State University campus. While there are a number
of fences in this portion of the campus, they are not high enough
to impede white-tailed deer movements and deer are free to roam.
Twelve experimental plots were established by clearing an area of
approximately 2.5 x 2.5 feet of all vegetation. Plots were spaced
at about 10 to 12 foot intervals. Cracked corn was used as bait to
attract deer to the plots. Each plot was baited with 2- 3 cups of
corn which was periodically replenished for about three weeks prior
to application of the repellent. By the time the repellent was applied,
all twelve plots were each being visited by 2 - 5 deer in a three-day
period.
To initiate the experiment,
on November 17, 1995, repellent was placed in six of the twelve
plots (the Treated plots); the remaining
six plots (the Untreated plots) did not receive any repellent. The
repellent was applied to the plots by attaching a bag of Green Screen
about 1 foot above ground level to a 2 foot long stick placed in
the center of the treated plots. Every third day the plots were checked.
The number of approaches to each plot was measured by counting the
number of distinct sets of deer tracks in the cleared area. After
counting the tracks, the plot was raked to remove old tracks and
2 – 3 cups of corn was added to the plot.
Results
The number of times white-tailed deer approached each plot, followed
the initial application of Green Screen on November 17,
is presented in Table 1. Figures 1 and 2 show the total number
of approaches
to the Treated and Untreated plots per observation period and the
average number of approaches to the Treated and Untreated plots
per observation period, respectively. The results can be summarized
as follows:
Over the course of the study, Treated plots were approached by white-tailed deer
only 10 times, while Untreated plots were approached 95 times.
-
On average,
over the 18 day length of the experiment, each Untreated plot was
approached
1.7 times or about 0.09 times per day.
Or stated another way, on average each Treated plot would be approached
by 1 white-tailed deer about once every 11 days.
-
On average, over the 18 day length of the experiment, each Untreated
plot was approached 15.8 times or about 0.88 times per day. Or state
another way, on average each Untreated plot would be approached by
1 white-tailed deer about once every 27 hours.
-
On average, Untreated plots were over 9 times more likely to be
approached by white-tailed deer on any given day than were Treated
plots.
-
The study was conducted for six 3-day observation periods and there
were six Treated plots and six Untreated plots. This in effect results
in 36 Treated plots that could be visited by white-tailed deer and
36 Untreated plots that could be visited by White-tailed deer. Only
17% (6 of 36) of the Treated plots were approached by the deer, while
94% of the Untreated plots were approached by deer.
-
The number of
white-tailed deer approaching Untreated plots was significantly
higher than
the number approaching Treated plots (Chi
Square test, P <0.001).
-
The number of
Untreated plots approached by white-tailed was significantly higher
than
the number of Treated plots approached (Chi Square test,
P <0.001).
-
Untreated plots
were significantly more likely to be approached by white-tailed
deer
on each observation day expect 11/20, the first
observation day after the repellent was applied (Kruskal – Wallis
test)
