Their habitats are being developed. Their preferred prey are declining. So why is New Hampshire’s bobcat population looking so strong?
That’s the question at the center of a University of New Hampshire study started this month by Marian Litvaitis, a professor of natural resources and the environment. And it may explain about more than just bobcats.
“Identifying the pathways of this success may provide insight into understanding how ecosystems can remain relatively intact as human population continue to expand,” Litvaitis said.
Researchers hope to learn how the state’s estimated 1,400 bobcats have replenished their numbers, given the detrimental factors in their environment. Some estimates put the low point for the species at about 200 animals in 1989, when the state banned trapping and hunting.
The researchers ask: How are bobcats making a comeback “despite a dramatic decrease in their traditional prey such as rabbits and hares.” And how has human development affected bobcats?
“We’re really interested in figuring out why they are able to rebound,” Litvaitis said.
Bobcats seem to have adapted to at least one new form of hunting, Litvaitis said, according to photos residents have sent the researchers.
The predatory cats, which weigh between 15 and 35 pounds, appear to be lying in wait on the outskirts of residential bird feeders. They’re not there for the songbirds, she said, but rather, they wait to pounce on turkeys and squirrels that clean up birdseed that has fallen to the ground.
“The bobcats just kind of ambush them,” Litvaitis said. “It’s pretty remarkable an animal can switch its prey like that. . . . Usually animals are fairly hardwired for their preferred prey.”
She added: “But if you look at house cats, you probably know they’re pretty smart animals.”
Those preferred prey include New England cottontails and hares, which themselves used to have a better habitat in New Hampshire, Litvaitis said.
European settlers cleared New England forests for farmland. Broadly speaking, they then ditched their farms and left the fields to grow young forests, including lots of brush and understory in which the rabbits could hide.
That was good for rabbit populations, and predators follow the prey numerically, Litvaitis said.
But as forests matured, the thicket grew more sparse, and so did the bobcats’ food sources. While the numbers of rabbits and hares remain low, the bobcats may have shifted to other food sources, scientists theorize.
Litvaitis said she’ll test the hair of bobcats found as roadkill in New Hampshire, Vermont and northern Massachusetts to examine isotope signatures and determine the content of their diet.
“Hair is a fairly long-term record,” she said.
She’ll also be able to detect whether bobcats living in more urban areas have higher levels of stress than their rural counterparts, she said, by comparing chemicals in the hair.
“Increased stress has been associated with a decreased immune response and decreased reproductive success in animal populations. Ultimately this may allow for projections about the general health of the bobcat population,” Litvaitis said.
Litvaitis, who has one doctoral student and one undergrad student working with her, said she expects to publish some of the data by November 2017. In the meantime, interested readers can follow along at the university’s bobcat research website: mlitvaitis.unh.edu/Research/BobcatWeb/bobcats.htm.