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1 November 2007 An Automated System for Detecting and Reporting Trespassing Bears in Yosemite National Park
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We developed and tested a system that alerts personnel when a radiocollared animal enters an area designated as off-limits. The remote alarm combines the monitoring capabilities of data loggers with a message transmitter that sends a voice message via 2-way radios when an animal enters a monitored area. We tested the remote alarm with food-conditioned American black bears (Ursus americanus) in Yosemite National Park by setting up 6 remote alarms in areas designated off-limits to bears (i.e., campgrounds and parking lots) and alternated nights when the message transmitters on the alarms were activated. We recorded the number of times a radiotagged bear entered an off-limits area, the number of times bear management detected a bear in areas off-limits, and the number of hazing events. Data loggers recorded 153 bear visits by 6 radiotagged bears, 59 with the alarm on and 94 with the alarm off. With the message transmitter activated, bear-managers found bears in areas off-limits 4 times more often than with the message transmitter off. Twelve hazing events occurred with the message transmitters active and 5 with them inactive. The number of bear visits/night to monitored areas was lower when message transmitters were active than when they were inactive, probably because bears entering areas off-limits were more likely to be detected and hazed with the message transmitter on. The remote alarm functioned well and aided park managers with their hazing program to reduce bear–human conflict.

Stewart W. Breck, Nathan Lance, Jean Bourassa, Sean Matthews, and Victoria Seher "An Automated System for Detecting and Reporting Trespassing Bears in Yosemite National Park," Ursus 18(2), 230-235, (1 November 2007).[230:AASFDA]2.0.CO;2
Received: 8 August 2006; Accepted: 1 February 2007; Published: 1 November 2007

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