Excluding Non-migratory Canada Geese with Overhead Wire Grids

Non-migratory urban Canada geese present complex problems requiring innovative techniques that are effective yet acceptable to contemporary society. A grid technique was modified and developed to discourage non-migratory urban Canada geese from using water sources and thus abandoning adjacent areas. The technique is believed effective because it restricts the use of water resources for escape and reduces the required long takeoff and landing zones of Canada geese. The grid successfully reduced non-migratory Canada geese from using three sites in northern Virginia. Several grid configurations and types of materials are discussed. Pro. East. Wild. Damage Control Conf. 6:85-88. 1995. Urban wildlife damage problems tend to be complex and require innovative strategies and methods for resolution. Complexities arise from the species non-response to traditional nonlethal methods, legal considerations, changing social values towards wildlife (Schmidt 1989), economic costs, and physical considerations. Finding an effective, yet social, legal, economic, and physically acceptable solution to an urban wildlife damage problem often directs the decision-making process through numerous fine-screened filters (Slate et al. 1992, USDA-APHIS 1993:2-24 to 2-31). The Virginia Dept. of Game and Inland Fisheries reported 37,000 non-migratory Canada geese living in northern Virginia in 1993 (G. Costanzo pers. commun.). The public has complained to state and federal wildlife and agriculture agencies about the geese defecating on beaches, lawns, and golf courses; depleting vegetative cover on shorelines; acting aggressive towards people; swimming in pools; becoming a hazard to aircraft operations; blocking roadways; and contaminating water quality. Nonmigratory urban Canada geese (Branta canadensis) in northern Virginia which I have worked with tend to show no response or limited short-term response to audio and visual harassment techniques (i.e., pyrotechnics, propane cannons, eye-spot balloons, mylar tape). Additionally, some county and city governments have passed noise ordinances which preclude use of audio harassment of Canada geese. Some urban residents consider certain nonlethal and lethal methods socially unacceptable (i.e., barriers, harassment, egg addling, relocation, etc.). And some effective control methods for Canada geese are economically prohibitive to landowners, businesses, and homeowner associations, or are aesthetically unappealing. Overhead wires were developed to exclude gulls from reservoirs (McAtee and piper 1936) and since have been used to exclude numerous other bird species (Pochop et al. 1990, May and Bodenchunk, unpublished data). The contorted decision-making process motivated me to seek an effective, economical, and practical method to the non-migratory urban Canada goose conflict in northern Virginia. This paper details my account in modifying and testing overhead wire grids to exclude non-migratory urban Canada geese from local areas. The author expresses gratitude to N. E. Myers, USDAAPHIS-ADC, Annapolis, MD; J. R. Thomas, VA. Dept. of Agriculture and Consumer Services, Harrisonburg, VA; J. F. Heisterberg, USDA-APHIS-ADC, Raleigh, NC; W. R. Fonwell, USDA-APHIS-ADC, Elkins, WV; K. A. Knight, United Rope Works, Montgomeryville, PA; S. D. Fairaizl, USDA-APHIS-ADC, Reno, NV; and L. E. Terry, USDAAPHIS-ADC, Annapolis, MD for assistance with design and construction of the grids. I also express appreciation to R. D. Owens and P. P. Woronecki for reviewing the manuscript. MATERIALS AND METHODS Overhead wire grids were installed at three locations located in Fairfax, Herndon, and Alexandria, Virginia. The first site was a golf course in Fairfax were a grid made of parallel 12-gauge polypropylene lines (National Netting, Norcross, GA) spaced 8.3 m apart and overlapping perpendicular lines 16.6 m apart were erected in January 1992 over a 0.8 ha pond. Four-foot fiberglass rod posts, spaced at 8.3 m intervals around the perimeter, supported the grid and two-strand perimeter line fence. The lines comprising the twostrand perimeter fence were 20 and 35 cm above the ground. The polypropylene line was connected to insulators using self stripping electrical tap connectors (3M Company). The maximum span over the pond was approximately 116 m. The second site was a corporation in Herndon were two grids were erected in May 1992 using parallel and perpendicular 12-gauge polypropylene lines spaced at 8.3 m intervals. Three-foot light-duty steel fence posts supported the grid. The polypropylene line was wrapped around the post and secured with a self-stripping electrical tap connector. The maximum span over the pond was approximately 83 m. A two-strand polypropylene line fence was erected around the perimeter as at the site in Fairfax. In April 1993 at the Herndon site a polypropylene line grid was replaced with 0.05 inch kevlar line (United Rope Works, Montgomeryville, PA) over one pond. The kevlar line was connected to heavy-duty five-foot steel fence posts by inserting a four-inch eye bolt through pre-drilled holes, sliding a 3/64 3/32 inch stainless steel thimble through the eye of the eyebolt, and threading the kevlar line through the thimble and a B4 cooper sleeve which was then crushed with a Nicopress No. 17-B4 hand tool (National Telephone Supply Co.). The eye-bolts were used to adjust the tautness on the kevlar lines; 1.5-2.0 kilos for spans less than 33 m and 3.253.75 kilos for 66-83 m spans. The kevlar line was rated at 85.6 kilos break strength. The two-strand perimeter fence was connected to the fence posts by passing the 12-gauge polypropylene line through one and one-half inch eye-bolts placed in predrilled holes about 20 and 35 cm above the ground. Self-stripping electrical tap connectors were used to connect the ends of the polypropylene ares. The third site was a golf course in Alexandria were parallel overhead kevlar lines spaced at 8.3 m intervals were installed over a 0.1 ha pond by the golf course following my instructions in the fall of 1992. A two-strand perimeter fence was not erected. The mention of products and corporations does not constitute an endorsement by the U.S. Department of Agriculture.