EVALUATION OF A CANADA GOOSE CALL-ACTIVATED SWITCH FOR CROP DAMAGE ABATEMENT

Damage and nuisance problems caused by Canada geese (Branta canadensis) are difficult to control with current abatement technology. We tested the efficacy of a goose call-activated switch as a modification for propane exploders (pas cannons), using recorded Canada goose calls and live goose trials. We recorded a 30 m range for the switch and found that it was activated by a range of non-target sounds. The development of this device and the technology involved are discussed. The call-activated switch is not a useful tool in reducing Canada goose damage in crop fields. Canada geese frequently feed on agricultural crops (Craven and Hunt 1984) resulting in unacceptable levels of damage (Hunt 1984). Crop damage has been a major management concern near Horicon National Wildlife Refuge (HNWR) for 28 years (Hunt and Bell 1973) and available abatement techniques are often,ineffective (Conover and Chasko 1985). Propane exploders are a common abatement tool (Besser 1985). They ignite a measured amount of propane at 20-30 minute intervals. The resulting explosion is intended to frighten geese away from the field. About 1,000 exploders are deployed near HNWR each fall to protect crop fields. Limitations on exploder efficacy and adverse public reaction to their noise led the Wisconsin Department of Natural Resources (WDNR) and the University of Wisconsin-Madison Department of Electrical and Chemical Engineering (UWECE) to examine possible 1/ USDA-Animal,Plant and Health Inspection Service-Animal Damage Control, Waupun, WI 53963 1/ Dept. of Wildlife Ecology, University of Wisconsin, WI 53706 improvements. One proposed modification was a call-activated switch that would use the vocalizations of Canada geese to activate the propane exploder. Such an exploder would be in operation only when it was needed, rather than on timed intervals. A call-activated switch offers many conceptual advantages. An exploder that would fire only when geese are nearby would result in less opportunity for habituation. A call-activated exploder would also require less maintenance, consume less propane, and reduce "noise pollution." Alternatively, the switch could be connected to other abatement devices; e.g., it could pop-up a scare crow, release a balloon, or activate a recording of distress calls or applied to other species. A functional call-activated switch would need to be highly sensitive to goose calls to offer a useful range (100 m). It must discriminate against other sounds present in the field to avoid frequent misfires and to be practical, the switch must be portable, inexpensive, and require little maintenance. Two years of UWECE developmental work resulted in a prototype switch (Brown 1978). The device used a ceramic microphone to receive incoming sound. It stored the key frequency and duration features of a Canada goose call in Permanent Read Only Memory (PROM) and compared the incoming signal to that profile. When a match occurred, it fired the attached device by activating a solenoid. The original prototype equipment was eventually turned over to the University of Wisconsin, Department of Wildlife Ecology (UWWE). We believed that this concept could be a solution to the complex problem of goose depredations in the Horicon area.