DNR Encourages Residents to Submit Black Bear Den Survey

Wednesday, March 5th, 2025 -- 9:00 AM

The black bear den survey season is winding down, and the Wisconsin Department of Natural Resources (DNR) encourages the public to submit any den locations they find across Wisconsin in order to help with ongoing black bear research.

The Black Bear Litter and Diet Survey aims to generate new estimates of black bear reproductive rates within each bear management zone and improve the accuracy of the population models used to manage them.

Additionally, researchers are investigating a connection between consumption of human food sources and bear reproduction since diet can affect cub survival rates and litter sizes.

After cubs are born, black bear dens get noisier. During this time of year especially, people might hear unusual small sounds such as squeaking, grunting, humming or sucking, which usually means the cubs are nursing.

After spotting a den, the public is encouraged to maintain a safe distance of approximately 30 yards and report the following information to the DNR:

• GPS coordinates
• A photo of the den, ideally showing it in relation to its surroundings
• Description of the site and surrounding area
• Any information on bear activity near the site, including whether cubs were heard

DNR staff will work with den reporters and landowners to visit the den before deciding to survey it, determining if the den is safe, accessible and in use. The research team may be unable to visit every reported den location this season.

Dens that are known to be currently occupied will be prioritized. DNR staff will collect biological data from these dens, including sex, weight and body measurements.

Mother bears, or sows, will be outfitted with GPS collars, one of the most important pieces for collecting data. Collars help staff learn more about bear foraging behavior and locate the sows in the following years.

Revisiting the sows will help staff determine the reproductive success of each sow, such as her litter frequency, litter size and the survival rates of the cubs. Data on sow weight, body measurements and age are also collected.

While surveying, bear health and safety are a top priority. Designated staff monitor the sow’s breathing and heart rate while the rest of the team quickly gathers the needed samples and measurements.

Any cubs present at the den are carefully weighed and sexed. Cubs are tucked into staff’s coats to keep them warm because the cubs cannot yet regulate their own temperature.

Once researchers are finished, the sow and cubs are put back into their den. To report a known black bear den, visit the DNR's black bear den submission form.

Feel free to contact us with questions and/or comments.