Demography changes from more hunters, less trappers for bobcats

As researchers noticed changes of bobcat (Lynx rufus) harvest over time in Wisconsin, they wondered if population models for bobcats based on harvest data were still accurate.

In a study published in Royal Society Open Science, a team of researchers looked at changing trends in bobcat harvest in Wisconsin in the last 30 years.

Hunters and Department and Natural Resources staff in the field reported seeing growing numbers of bobcats, but the model wasn’t showing an increasing population, said Max Allen, lead author of the study and assistant professor at the University of Illinois.

Reviewing harvest data collected from the Wisconsin DNR over 30 years, the team looked at type of harvest — trapping and hunting with hounds — as well as sex, weight and age at harvest. They noted that the number of tags issued each year had dropped substantially since the 1980s compared to neighboring states, but the bobcats harvested in Wisconsin remained the same.

Allen and his colleagues found that overall, more bobcats had been hunted by hounds compared with trapping, and animals harvested by hound hunters are more likely to be larger, older males.

“We’re seeing hound hunters selecting for large males,” he said. “Hound hunters are more likely to create a taxidermy mount for their harvest. This correlates with selection for larger trophy animals.”

Hound hunters have more opportunities to select a desirable animal to harvest and can seek larger individuals, Allen said, whereas trappers are less likely to release a bobcat once it’s in a trap, regardless of size.

Since population models are often based on the demography of hunted bobcats, Allen said, the animals hunted may not be representative of the entire population.

“At least in Wisconsin we haven’t had to account for trophy hunting in furbearers, so we have to change the population model to account for these changes,” he said.

To do so, Allen and his colleagues plan to apply advanced statistical techniques and create a Bayesian space-space model while also accounting for hunter selection.

“The human dimensions of wildlife can have substantial effects on the harvest, and these things change over time,” Allen said. “We need to keep analyzing and understanding these patterns and update population models to take those changes into account.”