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Deer Exclusion Devices and Deterrent Techniques

EVALUATION OF THE EFFICACY OF VARIOUS DEER EXCLUSION DEVICES AND DETERRENT TECHNIQUES FOR USE AT AIRPORTS

4. Review Methodology

worldwide literature, including unpublished "grey literature" sources, communication with wildlife workers including airport managers, game farm owners and staff at public zoos. The literature was assembled from the major wildlife damage control journals and conference proceedings, such as the Journal of Wildlife Management, Wildlife Society Bulletin, Proceedings of the Vertebrate Pest Conference, and Proceedings of the Eastern Wildlife Damage Management Conference. The publications of the International Bird Strike Committee/Bird Strike Committee Europe and Bird Strike Committee Canada were also reviewed. There is a relatively small literature pertaining to deer control at airports. To increase the available literature concerning deer control, studies relating to protection of agricultural and residential land uses have been integrated into this report to provide information that may not have been previously available to airport managers.

The information available on deer control products and techniques is usually inadequate to support objective quantitative evaluations of their effectiveness. There are few comprehensive, properly designed quantitative studies. Consequently, in many cases evaluations must be subjective. In part, this is because it is difficult to compare products and techniques. A myriad of difficult-to-control variables affects the performances and thus the comparative evaluations of deer control products. Products can be presented in a variety of situations and combinations. Complex environmental factors determine the effectiveness of various techniques. Often a product on its own is largely ineffective because of habituation, but can be an effective part of a multi-product/method approach. Especially important to know is whether occasional killing was employed to reinforce the product/method. All these factors make it difficult to compare products/techniques, or even the same product/technique in different places.

Reliable estimation of costs was often not available for many deer control methods due to lack of documentation, the exclusion of personnel costs and installation costs, the area and topography of application and/or the old age of many literature sources.

A series of questions was developed to address the difficulties associated with product/technique comparisons and evaluations. These follow below.

  1. What is the biological basis for the control measure? Is there a biological reason to expect the measure to be successful?
  2. Were the tests/examples of various fencing techniques conducted long enough to demonstrate that the deer will not find a way to penetrate a fence? Were the various fence designs effective? Are electric fences an option around a large airport property? Is intermittent electrification effective?
  3. What design criteria are the most important determinants of successful exclusion of white-tailed deer? Fence height? Mesh size? Type of material? Habitat on each side of the fence?
  4. Were the costs of various fence types reasonable given their level of effectiveness? Was the fence durable? Were maintenance costs and efforts reasonable? Were construction costs reasonable given the long lengths of fence that are required at airports?
  5. Were there any special circumstances associated with a particular situation or test that allowed the measure to succeed? Would the measure be less successful in other situations where the special circumstances were not present?
  6. Would the techniques that are successful for other ungulate species be successful for white-tailed deer?
  7. Are there any objective data available? It is important to distinguish between manufacturer's claims and independently demonstrated effectiveness.
  8. Does the success of a particular fence type depend upon the skill and knowledge of the installer and/or maintainer?
  9. Is there a potential for other techniques (e.g. cattle gates, predator scents, noise) to successfully complement the effectiveness of fencing/exclusion techniques?
  10. Are there options for altering habitat on the airfield to reduce its attractiveness to deer?
  11. Depending upon the severity and frequency of a particular problem, is shooting or live-trapping an effective option?
Date modified:
2010-05-03