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COLLEGE STATION – A year-long study on the Texas A&M University campus recently showed that males are more likely than females to die on the road, and scientists believe it's because the males dart about through the streets more.
But wait. It was urban squirrels, not students, who were radio-tagged and followed around campus. The research was instigated by Dr. Roel Lopez, wildlife and fisheries sciences assistant professor, both to find out about the 350-or-so fox squirrels on the campus and to teach undergraduate students how to trap, handle and monitor animals.
"First year survival was 80 percent for females and 74 percent for males," Lopez said. "And interestingly, we found that highway mortality accounted for 100 percent of the male squirrel mortality." Male squirrels went a daily distance of about 54 feet and covered a range of about 4.7 acres compared to females who daily went about 38 feet in a 3.4-acre range, Lopez noted.
Female squirrel death was mostly attributable to predation, he said.
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"This was a unique opportunity to combine wildlife research with academic training - putting theory and application in the field - for students here on the main campus," Lopez said. "The information we gathered gives us a basic understanding of how to manage squirrel population in urban landscapes and an effective teaching medium for students learning in a classroom about the population dynamics of wildlife species."
Lopez said the research, the first of its kind on urban squirrels in the United States, is important because urban sprawl is pressuring wildlife to adapt to lifestyles and surroundings just to survive.
"In some cases, wildlife species have adapted within or adjacent to urban landscapes, resulting in new challenges for wildlife biologists faced with managing these populations," Lopez said.
He noted that fox squirrels have become increasingly of interest to biologists as they have adapted to living in cities, because their presence in large numbers may have an impact on landscapes and diseases. But little is known about fox squirrels in Texas, so Lopez and his students made the 400-acre park-like campus their laboratory for study. They trapped 20 squirrels, fitted each with a miniature collar equipped with a battery-powered transmitter, and released each squirrel within 15 minutes of capture.
The radio-collared squirrels were monitored five to seven times a week by undergraduate and graduate students using homing devices, Lopez said. Data for each squirrel was recorded and used to calculate movement and ranges.
More than 100 students participated in the study, and nine students earned hands-on internship credits required for graduation. Lopez said that's important because preparing people for careers in wildlife management is difficult with budget and time constraints, yet experience with wildlife in real situations is vital.
"We plan to continue to monitor marked squirrels on campus for another year," Lopez said. "In the near future, we hope to monitor squirrel reproduction with the aid of miniature cameras placed in nest boxes and viewable via the Internet."
The project was funded by the Ed Rachel Foundation and the Texas Agricultural Experiment Station. Information about the projects is at http://agc.tamu.edu/squirrel/