Black Bear Population Patterns in New York

May 10, 2017
Kerry Lengyel

Since the early 1990s, the black bear population in southern New York has been growing and expanding its range across the state. Researchers are now trying to learn more about the black bear population and density in this region.

Details about New York’s black bear population largely have been understudied, but now researchers from Cornell University are changing that.

The research team, whose findings were published in the Journal of Wildlife Management, estimated the densities of black bears (Ursus americanus) in southern New York and how they are distributed relative to the amount of forest, agricultural lands, and human development in the study area.

“Black bears are encountering human populations more now than they ever have before,” said Catherine Sun, a doctoral student in the Department of Natural Resources and the paper's lead author. “Our study shows how bears are distributed on the landscape at the edge of their range and provides clues for how bears might continue to use landscapes farther north.”

In New York, there are 3 bear ranges: the Adirondack, Catskill, and Allegheny mountain regions. Researchers focused on the Catskill and Allegheny ranges, which cover the entire southern region of New York, when conducting their research. “That's where a lot of the population growth has been so that's where we wanted to put our research efforts,” said Sun.

Researchers set up close to 200 research sites using barbed wire to obtain hair samples from bears that would pass by. The sites stayed active for 2 summers, and then researchers extracted DNA from the hair samples and identified which bear left each sample. In all, they collected about 2000 hair samples from 257 bears.

“We are using a noninvasive genetic approach, an important new method that wasn't available 15-20 years ago,” said Angela Fuller, an associate professor of natural resources, leader of the New York Cooperative Fish and Wildlife Research Unit, and a co-author of the paper. “In the past, we had to go out and capture and then physically tag each bear.”

The study team concluded that there are about 13 bears per 38.6 square miles—or 1 bear for every 3 square miles—in the southern New York area. The study also showed that as the sites moved north, bear densities decreased slightly.

“There might be limited constraints to bears continuing to move northward because they are using a diversity of land cover types,” said Fuller. Even so, the researchers believe the bear population will likely expand farther north into areas that have higher human populations.