Field Journal: How to Collar A Bear

From the Field posts

Rae Wynn-Grant is a conservation science research and teaching postdoctoral fellow jointly appointed with the Center for Biodiversity and Conservation and the Museum's Education department. Her work explores the influence of human activity on large carnivore ecology. Dr. Wynn-Grant is currently studying the impacts of human activity on landscape use, habitat suitability, and habitat connectivity of black bears in Nevada, where she was conducting her research when she wrote this field journal last month.

Tracking the movement of bears in the wild helps us learn more about how these animals interact with humans, and how tensions between the two species can be eased when their habitats overlap. To understand how bears and humans live together, though, we first have to learn where the bears are, and that means finding—and trapping—black bears.

During the last seven years, my research collaborators and I have attached GPS collars to more than 25 black bears in order to track their movements and study their habitat selection. To do this, we set traps in both backcountry mountain regions and places at the urban-wildland interface. That’s what we’re doing in the field right now.

large male black bear

A large male black bear photographed by a camera trap in the Nevada backcountry. He was attracted to the site by the scent of raspberry essence, visible on the leftmost tree. 

© R. Wynn-Grant


We use humane barrel traps in our fieldwork—essentially large cages that are roomy enough for an adult bear, as well as one or two cubs—because they don’t harm the animals. These cages are baited with fruit and other sweet-smelling foods—when the bear enters for a meal, the cage door shuts behind it.

Once the bear is caged, we tranquilize it briefly in order to attach a GPS collar that allows us to keep tabs on it. While the bear is asleep, we also take blood and hair samples for DNA analysis, weigh and measure it, and give it an ear tag that allows us to identify it if it is captured again.

Humane barrel bear trap

A barrel trap similar to the ones used by Dr. Wynn-Grant to trap and collar bears without injuring them.

© R. Wynn-Grant


Collaring isn’t forever, though. We want to learn as much as we can about as many bears as we can, so every couple of years, we take the GPS collars off of bears that we’ve gathered data on and place them on new animals.

Trapping this year has been challenging. As opposed to the last few years of extreme drought, 2016 has been very wet so far; in fact, it has rained or snowed each day that I’ve been out here. While this is fantastic for the water-starved environment, it’s not great for luring bears to traps. Many bears are still hibernating in the areas that still have snow cover, while those who are awake are finding plenty of food throughout the forest, making the scents coming out of our traps less attractive. So we’ll continue to watch and wait! 

To learn more about Dr. Wynn-Grant's work, you can read here other posts from the field here and here