Photo ID (L Stephanie Tucker R Cami Wright) NDGF biologists necropsy
By Doug Leier
It’s been nearly 20 years since the first legal mountain lion season in North Dakota.
To think there’s a generation that has grown up never knowing a time when there wasn’t a season. It puts into context the label of “new” or “experimental” when describing one of the more recent additions to legal take in our state. It is new compared to deer, grouse and pheasants or ducks and geese.
Maybe it fits best when considering new seasons for other furbearers like river otters and fishers, which were added more recently. These more recent additions to hunting and trapping require close monitoring of populations to ensure a sustainable harvest and population.
No matter the designation, these smaller yet intriguing species create a unique discussion with population assessment. While upland and big game have years of sampling and confident means through live surveys over decades, lower populations and the discreet behavior require biologists to utilize other means to survey some furbearers.
Mountain lions are an interesting study to explain how wildlife managers look at these unique North Dakota species.
“They have really low densities on the landscape, they have huge home ranges, they’re nocturnal and very secretive even when they’re moving about during the day,” said Stephanie Tucker, North Dakota Game and Fish Department game management section leader. “Which means we can’t drive around and count them or even go up in an airplane and count them. So, we have to come up with other ways to survey the populations and monitor those population trends.
“And that is especially important if we have an open hunting or trapping season on that animal,” she added. “We need some way to monitor those populations and ensure that our hunting and trapping seasons are either having the impact or not having the impact depending on what our population management goals are for that species.”
Game and Fish manages many of these furbearer species through necropsies, which is basically autopsies on animals.
“Mountain lions, bobcats, river otters and fishers are four of the species of furbearers in North Dakota that we require hunters and trappers to relinquish the carcass to us after the pelt has been removed,” Tucker said, “and we’re just using that necropsy to collect some very basic demographic and reproductive information about the animals so that we can survey them.”
While Tucker and staff can learn a number of things about an animal through a necropsy, what’s vital is to understand if the population of the furbearer on the examination table is increasing or decreasing.
“For my purposes, when creating a population model, there’s really two important pieces of information. We want to know how old the animal is when it died to estimate survival based on that age information,” Tucker said. “And the second thing is we want to find out if it is a female, was she reproductively active in the last year? And if so, how big was that litter that she might have had.”
Tucker said biologists are trying to determine through information on survival and reproduction if the population is increasing or decreasing. Which is why it’s vital that hunters and trappers help in the effort to collect enough mountain lion, bobcat, river otter and fisher carcasses to create population models to monitor trends.
This information is necessary in assisting wildlife managers in setting furbearer seasons and limits.
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