Progress 10/01/01 to 09/30/06
Outputs
In 2001, after 10 years of controversy surrounding white-tailed deer management, the City of Highland Park chose to study the use of surgical sterilization of female white-tailed deer as an alternative means of controlling its deer population. No previous attempts have been made by wildlife ecologists to assess the efficacy of surgical sterilization to control urban deer populations. Preliminary data on the efficacy of sterilization, as a means of controlling deer on the grounds of the Milwaukee County Zoo, Milwaukee, WI, suggested that this technique held promise for small geographic areas. In 2002, the Illinois Department of Natural Resources approved a Scientific Permit for a research study to assess the success of sterilization in controlling the growth of the deer population within the city limits of Highland Park. The 12.5 mi2 area of Highland Park was divided into 2 study areas: a control side (4 mi2) and treatment side (8.5 mi2. Using standard deer trapping
protocol, 180 deer were captured between 2002 and 2004, and 67 females were surgically sterilized. Capture-related mortality was 6%. Over the course of the study, more treatment deer (27.6%) died than control deer (12.7%), with car collisions accounting for most of the deaths. We found that sterilization can control the deer population in Highland Park at the goal population level of 5 deer per mi2, if we can capture and sterilize an average of 32% of the female population per year. Our computer model suggests that the long-term maintenance of the population will require sterilizing an average of 6 does per year. Sterilizing more females will result in achieving the population goal more quickly. The model projections suggest that the population will continue to grow initially and peak at 3.7 years, until the effects of sterilization halt population growth. There after, the population will decline and hover around the target density after 9.5 years. We evaluated the influence of
sterilization on the behavior (home range size and dispersal rates) of the sterilized and control deer. In general, deer used extremely small home ranges in this urban environment and there were no differences in either the home range sizes or dispersal rates of sterilized deer verses the control deer. Fawns used larger home ranges than adults, and home ranges were larger during the winter. Although the sample size is exceedingly small, we found that more treatment deer than control deer made exploratory movements out of their home range. There is also an initial indication that sterilized deer traveled farther and used larger home ranges than control deer. Although the initial start-up costs for the project were high due to the research aspects of the study i.e.(radio telemetry), we estimate that deer could be sterilized for a base cost of $750 per deer under a management, rather than research, regime.
Impacts
The results of this research suggest that, under a narrow set of conditions, surgical sterilization can be effective in controlling the growth of an urban white-tailed deer population.
Publications
- MacLean, R. A. Jr, E. S. Frank, J. Paul-Murphy, and N. E. Mathews. 2002. Tubal ligation as a means of controlling a population of urban white-tailed deer: Preliminary results. American Association of Zoo Veterinarians. Conference Proceedings.
- Mathews, N. E., J. Paul-Murphy, and E. S. Frank. 2005. Evaluation of a trap-neuter-release program for white-tailed deer management in Highland Park, Illinois, 2002-2005. Final Report for Highland Park City Council. 52 p.
- Mathews, N. E. 2005. Influence of white-tailed deer behavior on transmission of chronic wasting disease in south central Wisconsin. Yearly progress report, Wisconsin Department of Natural Resources. 4 p.
- MacLean, R. R., N. E. Mathews, D. M. Grove, E. S. Frank and J. Paul-Murphy. 2006. Surgical technique for tubal ligation in white-tailed deer (Odocoileus virginianus). Journal of Zoo and Wildlife Medicine (In Press).
- Gilman, R. T, N. E. Mathews, J. Paul-Murphy, and E. S. Frank. 200x. Demographic stochasticity models to predict time-optimal sterilization rates for control of overabundant deer. Ecological Modelling (Submitted).
- Skinner, B., N. E. Mathews, J. Paul-Murphy, E. S. Frank, R. A. Maclean, D. Grove, and V. B. Julius. 200x. Behavior and movements of surgically sterilized white-tailed deer in an urban environment. J. Wildlife Management (submitted).
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Progress 01/01/03 to 12/31/03
Outputs
Project Background: This research is designed to test the efficacy of female deer surgical sterilization as a means of regulating population growth of the white-tailed deer population in the 12.5 square mile Highland Park, IL. We hypothesize that sterilizing 80-90% of breeding does will lead to a stable or declining population in a 4 year period. Our preliminary modeling suggests that at this rate of sterilization, we will reduce the current deer density from 8/square mile to 5/square mile, or a female population of 4/mi2 to 2.5/mi2 in 4 years. Project Goal: Investigate whether surgical sterilization of female deer can regulate a population of white-tailed deer within a 4 year period. Project Objectives 1) Assess the efficacy of surgical sterilizations of female white-tailed deer as a means of limiting recruitment. 2) Assess the demographic impacts of sterilization at the levels of the population and social group. 3) Assess the behavioral impacts of sterilization at
the levels of the populations and social group. 4) Evaluate the cost effectiveness of surgical sterilizations for use as a realistic population control technique in an urban area. Summary of Trapping: treatment does 27, control does 13, bucks 28, recapt does 22, recapt bucks 43,total # deer 111. Deer Mortalities: treatment does 0, control does 3, marked bucks 2, unmarked does 1, unmarked bucks 1, total 7. Preliminary Implications: The results of this research are currently being analyzed to determine the impact that sterilization has had on the population demographics to date. Radio telemetry analysis suggests that does of both treatment groups use exceedingly small home ranges. Adult mortality rates are higher than expected due to numerous car collisions.
Impacts
The results of this research will either support or refute the use of surgical sterilization of female deer as a means of urban population control.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
This research is designed to test the efficacy of surgical sterilizations as a means of regulating population growth of the white-tailed deer population in the 12.5 mile square Highland Park, IL. We hypothesize that sterilizing 80-90% of breeding does will lead to a stable or declining population in a 4 year time period. Our preliminary modeling suggests that at this rate of sterilization, we will reduce the current deer density from 8/square mile to 5/square mile, or a female population of 4/square mile to 2.5/square mile in 4 years. During the first year of research we had a total of 133 captures of 88 deer. Mortality rate due to project activities was less than 6%. A total of 24 females were sterilized. Evaluation of success of sterilization as a means of population control will require a minimum of one additional year of data acquisition.
Impacts
Resistance to hunting or sharp shooting white-tailed deer in urban environments is growing and there exists no reliable means of controlling deer using non-lethal techniques. If the reslults of this research indicate that sterilization of female deer successfully slows the rate of population growth in an urban environment, then wildlife ecologists will have a new tool for urban deer management.
Publications
- No publications reported this period
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