Vermont Fish & Wildlife staff measure a black bear as part of a newly launched survey this summer. Photo courtesy of Vermont Fish & Wildlife Department.
For the fourth year in a row, Vermont’s black bear population size far outpaced what the state projected.
Last year, the state had an estimated 6,800 to 8,000 bears, nearly double the objective of 3,500 to 5,500 bears, outlined by a Vermont Fish and Wildlife Department population model.
Why is the population doing so well? There are two big factors that determine population size, said Jaclyn Comeau, the Black Bear Project leader at the state Fish & Wildlife Department: mortality rates and reproduction rates.
The state has a pretty good sense of what is influencing bear mortality, she said. Hunters are responsible for most premature bear deaths, followed by vehicle collisions. Freak accidents, like a bear chewing an electrical wire, can also cause a bear’s early death. Still, populations are continuing to “grow and grow,” Comeau said.
Looking at reproduction is “kind of that missing piece of information that we don’t have” when it comes to understanding what drives that trend, according to Comeau. A new study launched this summer aims to tackle that question and better pinpoint what type of habitat and food availability supports healthy bear birth rates.
Since the 1980s, the “backbone” to steady population growth has been the wider recovery of suitable habitat for bears, Comeau said, as forest grew back across a landscape previously dominated by deforestation and farm land. The agricultural Vermont of the 1940s and 1950s left bears confined to the spine of the Green Mountains, she said. In those days, killing bears was far more common, without the hunting regulations and restricted season Vermont has today.
Still, the Fish & Wildlife Department would like to better understand how availability of different food sources might influence where the bears go and how successful they are in reproduction, especially as they spread down from the mountains.
In the mountains, beechnuts are bears’ primary fall food source, but the trees’ nut production pulses every two or three years. Historically, bear populations have risen and fallen with these cycles.
In the valleys, oak trees — and thus, acorns — are more abundant and more consistent.
“We’re wondering if now that the bear population has moved out of the mountains, if they’re accessing higher-quality habitat where food is more consistent,” Comeau said. “Now that they’re in the valleys, potentially, the habitat might be more productive and allowing their populations to grow.”
To answer that, the department’s study follows 18 adult female bears fitted with GPS tracking collars that allow biologists to see where the bears are, presumably getting food. The study aims to isolate these two distinct habitat areas by looking at nine bears in the Connecticut River Valley and nine others in the southern Green Mountains. In the winter, the scientists will visit the bears’ dens to confirm how many cubs the mother has, with the intent of following the family and cub survival through their first year of life. Fish & Wildlife anticipates letting the survey run for six years in order to collect enough data to draw conclusions.
Better understanding the conditions in which bears are thriving will allow the department to better protect and manage their habitat, Comeau said.
The prosperity of Vermont’s black bears is a rare success, as many species decline due to habitat loss, changes in food availability and environmental shifts, among a range of other environmental shifts brought on by climate change.
Black bears are especially flexible when it comes to habitat and food. As omnivores, they can survive off multiple food sources, and their wide range, from Florida and Mexico to Canada, shows they can adapt to a variety of habitats and temperatures.
Still it does not mean that a changing climate will leave the bears unaffected, Comeau said.
Comeau worries what the encroachment of beech leaf disease in Vermont’s forests will mean for the bear population over the next decade.
And as Vermont’s winter season shrinks, people should expect bears to enter hibernation later in the year and emerge earlier in the spring. That, plus a growing population spreading beyond the mountains, makes bears more likely to encounter humans. For Comeau, this underscores a need to figure out how to foster the best coexistence.
The department added that Vermont’s bear hunting season started Monday and runs through Nov. 14. Hunters are allowed to kill collared bears, but Fish & Wildlife asks that they avoid killing bears accompanied by cubs and that they return any collars.