Managing Canada Geese in Urban Environments a Technical Guide Arthur E
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Managing Canada Geese in Urban Environments A Technical Guide Arthur E. Smith, Scott R. Craven, and Paul D. Curtis A publication of Cornell Cooperative Extension, the University of Wisconsin, The Jack H. Berryman Institute, Utah State University, and The Wildlife Society, Wildlife Damage Management Working Group Arthur E. Smith is a research intern and Scott R. Craven is an extension wildlife specialist with the Department of Wildlife Ecology, University of Wisconsin, Madison. Paul D. Curtis is an extension wildlife specialist in the Department of Natural Resources, Cornell University. Acknowledgments We especially want to thank M. R. Conover and the Jack H. Berryman Institute, Utah State University, Logan, Utah, for reviews and support in producing this manual. The Wildlife Society–Wildlife Damage Management Working Group’s Urban/Suburban Canada Goose Task Force Committee also provided review and support for this manuscript. We also thank S. Beckerman, H. Blokpoel, E. C. Cleary, R. A. Dolbeer, M. E. Eckstrom, G. Haas, R. S. Lutz, P. J. Rodrick, K. Solberg, W. E. Wheeler, P. C. Whitford, members of the Mississippi Flyway Council Technical Section Giant Canada Goose Committee, especially G. Zenner and J. Bergquist. This publication should be cited as Smith, A. E., S. R. Craven, and P. D. Curtis. 1999. Managing Canada geese in urban environments. Jack Berryman Institute Publication 16, and Cornell University Cooperative Extension, Ithaca, N.Y. Additional copies of this publication may be purchased from Cornell University, Media and Technology Services Resource Center, 7 Cornell Business & Technology Park, Ithaca, NY 14850. Phone: 607-255-2080. Fax: 607-255-9946. E-mail: [email protected] A free catalog of Cornell Cooperative Extension publications and audiovisuals is available from the same address, or from any Cornell Cooperative Extension office. The catalog also can be accessed at the following World Wide Web site: http://www.cce.cornell.edu/publications/catalog.html ISBN 1-57753-255-4 Contents About This Guide . 4 Introduction . 5 Biology of the Canada Goose . 7 Regulations Covering Canada Geese . 9 Management Strategies. 9 Techniques . 11 Summary. 28 References . 29 Appendixes . 33 A. Equipment Suppliers . 33 B. Suppliers’ Addresses . 35 C. Summary of Techniques. 38 Managing Canada Geese in Urban Environments 3 About This Guide This manual is intended for anyone concerned with urban elsewhere but spend part or all of the fall to early spring Canada goose management. We define urban geese as those period in urban or suburban areas. Although this guide that spend most, if not all, of their life in the urban or sub- emphasizes Canada geese, many of the techniques and urban environment. This includes resident geese as well as management strategies listed are also useful for ducks, those commonly referred to as “migrants,” which summer swans, and perhaps other waterfowl species. 4 Managing Canada Geese in Urban Environments Introduction Canada geese are perhaps the most widely recognized birds cleaning goose droppings from sidewalks cost more than in North America. Geese flying in a V formation signal $60 per bird (Allan et al. 1995). changes in season and for many people have come to sym- Heavy concentrations of goose droppings contain nitro- bolize nature and wildlife. gen, which can result in eutrophication of ponds and lakes, In the early 1900s, Canada goose populations were near- leading to excessive algal growth (Kear 1963, Manny et al. ly eliminated in most parts of North America by unrestrict- 1994), closure of public swimming areas, and reduced ed harvesting of eggs, commercial hunting, and draining of water quality. Goose droppings do not appear to add nitro- wetland habitat. Thanks to enactment of strict harvest reg- gen to a feeding area because most nutrients originate from ulations, creation of protective refuges, changes in crop the grass of the same area (Groot Bruinderink 1989); the planting and harvesting techniques, and creation of large, nitrogen in the droppings, however, may be in a form that open grassy areas, most Canada goose populations have is more available to plants and thus overfertilize an area. rebounded and are no longer at risk. This astounding Besides the direct impact of Canada geese residing in recovery occurred partly because Canada geese adapt urban areas, they can act as decoys for migratory geese, readily to habitats found in urban and suburban areas. causing periodic increases in urban goose populations. Scientists recognize several “races” or subspecies of Geese in urban areas are very aggressive around their nests Canada geese. The geese most commonly found in urban or goslings and may attack or threaten pets, children, and areas during spring and summer in the eastern and mid- adults. western regions of the United States and Canada are called Geese will also trample grass in medium-heavy soils, giant Canada geese (Branta canadensis maxima), whereas which creates a surface “hard pan” that prevents vegetative those found or observed in urban areas during the spring growth (Traill-Stevenson 1988). This causes erosion and and summer in western regions of the United States and loss of habitat for other species (Wall 1984). Geese in high Canada are called western Canada geese (Branta canadensis concentrations or even a smaller flock that remains in the moffitti). These two subspecies have the largest body sizes of same place for an extended period of time may overgraze the many races of Canada geese. the grass (Conover 1991), creating large, dead spots on The giants have undergone a phenomenal population lawns. increase from only a few thousand in 1965 (Hanson 1965) High concentrations of geese increase the likelihood that to an estimated 1.1 million in 1996 (Wood et al. 1996) in avian diseases will be transmitted, creating the potential for the central United States alone. This growth rate is not massive die-offs. Disease organisms originating from a sin- peculiar to North America; in Britain, numbers of Canada gle species of waterfowl can also spread to other species geese increased by an estimated 8 percent annually from (Friend 1987). Diseases such as coccidoisis, avian influenza, 1976 to 1991 (Allan et al. 1995). Lesser Canada geese schistosomes, chlamydiosis, salmonella, and avian cholera (Branta canadensis parvipes), usually thought of as migrants, are transmitted under these circumstances (Guth et al. have bred in Anchorage, Alaska, since the early 1970s, and 1979, Skene et al. 1981, Friend 1987, Webster et al. 1993, their numbers have been increasing (Laing 1997). Although Gomis et al. 1996). Canada geese are suspected of transmit- a few geese may be desirable in a park, suburban pond, or ting salmonella to cattle (Lowney et al. 1997). Transmission backyard, such small populations increase rapidly and of disease or parasites from geese to humans has not been sometimes lead to problems that can be difficult to control. well documented, but the potential exists (Luechtefeld et al. Conflicts between Canada geese and humans in the 1980, Wobeser and Brand 1982, Hill and Grimes 1984, urban environment have increased as goose populations Pacha et al. 1988, Blankespoor and Reimink 1991, Graczyk have grown (Conover and Chasko 1985). Geese may be et al. 1997). only a nuisance owing to their droppings, aggressive behav- Because geese like open, grassy areas, are large, and tend ior, and noise, or they may represent a potential serious to form flocks, they may possibly strike airplanes at airports environmental threat or risk to human health and safety. (Milsom 1990). Most modern aircraft are engineered only Urban Canada geese may also fly to surrounding agricultur- to withstand the impact or engine ingestion of a single 1- al lands to feed on crops such as corn, soybeans, rice, win- to 3-pound bird. At the Reno-Sparks, Nevada, airport from ter wheat, and other grains. 1986 to 1989, Canada geese were involved in 11 airplane A common complaint about geese is the accumulation of strikes, costing a total of $250,000 in damage. The Federal droppings and feathers. Sixty geese seems to be a threshold Aviation Administration (FAA) threatened to close the air- for complaints about goose droppings (J. Cooper, port if it did not institute goose control (Fairaizl 1992). In University of Minnesota, pers. comm.). In one park in 1995, a U.S. Air Force Boeing 707 E-38 AWACS jet took London, England, reestablishing overgrazed lawns and off from Elmendorf Air Force Base, Alaska, and ingested at Managing Canada Geese in Urban Environments 5 least 13 Canada geese. The $184 million aircraft crashed, fowl involved in bird strikes against U.S. civil aircraft from and the entire 24-person crew was killed. Also in 1995, a 1992 to 1996 (Cleary et al. 1997). The FAA estimates that Concorde jet lost two engines after ingesting several geese 240 goose-aircraft collisions occur annually. while landing at the John F. Kennedy Airport in New York, As a result of the increasing numbers of geese living in and a similar event occurred at New York’s La Guardia urban landscapes, some major metropolitan areas in the Airport. Pacific, upper Midwest, Northeast, and mid-Atlantic states Waterfowl accounted for 35 percent of all reported mon- are faced with the increasing challenge of balancing Canada etary losses resulting from wildlife strikes to U.S. civil air- goose use of urban sites with human needs. craft. Geese and swans comprised 58 percent of all water- 6 Managing Canada Geese in Urban Environments Biology of the Canada Goose Descriptions and General Behavior Craighead 1949); in central Wisconsin around April 4 Canada geese have gray-brown wings and backs; light gray (Collias and Jahn 1959); and in south central Ontario to dark brown sides and breasts; black tails, feet, legs, bills, around mid-April (Lumsden 1969, J. Sullivan, Canadian and heads; and black necks with distinctive white cheek Wildlife Service).