SciTech

Motion cameras record after-dark census of wild mammals

What animals do you see during a typical walk on your local greenway? You’ve certainly seen people and their dogs, probably a few squirrels, and perhaps deer if you travel quietly around dawn and dusk. Do you ever wonder what else is out there? What you might see on a quiet midnight walk through the woods?

A better option than staying up all night is to use camera traps – motion-triggered cameras that scientists use to record animals that live in a particular area. Last winter, a group of N.C. State students in a College of Natural Resources course did just that. Teaming up with biologists from the N.C. Museum of Natural Sciences and greenway planners from the Raleigh Parks, Recreation and Cultural Resources Department, the students placed 43 pairs of cameras along Raleigh’s greenways, half facing the trail and half in the adjacent woods.

During a six-week period, the cameras “captured” 2,579 pictures of 13 species of wild mammals. As you might guess, most were deer – approximately 46 percent. Others included gray foxes and raccoons (14 percent each) and eastern gray squirrels (8 percent). One beaver, a few red foxes, a river otter and four woodchucks were also recorded.

The cameras also recorded house cats 142 times – day and night. This may concern some animal lovers because cats have been blamed for the death of large numbers of birds and other wildlife. Cat lovers, in turn, may be concerned about the 111 coyotes photographed by the students’ cameras. The coyotes, known predators of house cats, were common on the greenways at night. Cat owners might want to think twice about letting their pets out after dark.

Our photos showed that most of these animals roam the trails and adjacent woodlands at night when people are not around to see them. In contrast, nearly all people (47,386 pictures worth) were out during the day, including a morning surge at 9 a.m. and an afternoon peak around 3 p.m. And about 1 in 7 of those people were walking dogs.

There’s more to learn about the wildlife on greenways, especially as coyotes continue moving in. Coyotes have been invading North Carolina since the mid-1980s and can now be found in all 100 counties. What are those wily coyotes doing? Are other species changing their behavior in response? Are house cats killing species that are of concern to conservation? Long-term data collected by camera traps and collars could help answer these questions: It beats staying up all night for weeks on end watching for cats and coyotes!

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