DURHAM — Eastern coyotes have been snatching pets since they came to the state more than 40 years ago, Patrick Tate, a wildlife biologist with New Hampshire Fish and Game, said Wednesday.

Last week, a Barrington woman watched her 17-pound Sheltie be taken into the woods by a coyote and is warning other pet owners to beware.

Tate said the state does not have hard numbers on the coyote population but said based on their “indices,” the coyote population in 2010-2011 was slightly down.

He said in mild winters, coyote populations do not fare as well, because they can prey on deer better in winters with heavy snow.

“They can catch various prey a little easier, and that allows them to have a higher reproduction rate in the spring,” Tate said. “When we have years with low snow, they can’t do as well feed-wise.”

He said this is a possible reason why a coyote might go after a domestic animal, and although this winter has been mild, the state has not received above-averages reports of coyote attacks on domestic animals this winter.

“Coyotes have been going after domestic dogs in low-number situations, and domestic cats,” Tate said.

He said coyotes are a “generalist species” and can become habituated to residential areas where they will look for food, which can lead to instances where they take off with a domestic dog or cat.

“They can learn to live out in large expanses of woods just fine, and they can learn to live on edges of cities,” Tate said.

Just a few days ago, he received a report of an Eastern coyote in Nashua.

“When it comes to coyote concerns or complaints or simply ‘I saw a coyote in the yard,’ I receive those calls statewide,” Tate said.

He said average Eastern coyotes weight 35 to 45 pounds but can appear larger because of thick fur. He said they are often mislabeled as wolves, but to date there is no documentation of free-ranging wild wolves in New Hampshire.

Under state law, property owners can have a “nuisance animal” like a coyote presenting property destruction or injury removed, and can also protect their property by lethal means, within state firearms laws.

“If a coyote is simply walking through the yard, that is a slippery slope. If it is in active pursuit of a dog or cat, that’s property, and they can take the coyote’s life,” Tate said.

He said Fish and Game always recommends pet owners be outside with their animal, as any number of animals, including fisher cats, foxes and even hawks are capable of taking small domestic pets.