News that a bear sow and her yearling cubs will be euthanized in Hanover has sparked outrage from Upper Valley residents, a petition to save the animals and a plea from an eminent bear biologist in Lyme.

State wildlife experts say the bears must be trapped and killed because, after eating from bird feeders and human trash and even entering a house, they appear to have become too accustomed to humans to become wild again.

In an interview today, the biologist, Ben Kilham, questioned whether killing the bears was a solution. Bear breeding season is approaching, which means that the female soon will send her cubs away in anticipation of a male’s arrival, Kilham said.

“If they’re willing to delay it,” he said of the euthanization plan, “the female’s going to drive her young off pretty soon.”

Kilham also said the town should address the underlying causes of bear incursions — garbage, bird feeders and chickens left out where bears can reach them — or else will face the same problem again.

“All you do is create a vacancy by killing the female and her cubs, which another bear will fill soon,” he said.

The town, Kilham said, “needs to get serious about passing an ordinance to control the behavior of people in Hanover.”

Kilham said Hanover should pass a town ordinance that imposes small fines, perhaps $10, in order to encourage residents not to leave out things that attract bears.

Hanover officials are encouraging landlords to invest in steeltop, bear-proof dumpsters.

More than 200 comments poured in to the Valley News Facebook page over the past day, the vast majority expressing concern or anger over the planned euthanizations. Valley residents also created a petition on the website Change.org in a bid to save the mother and her cubs. Nearly 1,300 people had signed it by early Thursday morning.

Many readers asked why it wasn’t possible to relocate the bears, but Kilham said that likely would be ineffective.

“The trouble with relocation is ... the state has a healthy population of bears and each female bear has a territory; she drives out other females unless they’re her relatives,” he said. Even if officials dump the mother bear 100 miles away, he said, “she’s going to be attacked by every bear along the way. She’s going to think of home and be home within a few weeks.”

Putting the bears in a refuge or a zoo wouldn’t work either, Kilham said, because those are already overcrowded.

Hanover Town Manager Julia Griffin said she had received several phone calls from upset residents in the past day.

“Once I take the time to explain to them the rationale for why relocation is not feasible given just how habituated they are to humans and human food, they have generally been understanding,” Griffin said.

As of mid-afternoon today, no bears had been caught, Griffin said.

Griffin also addressed Kilham’s point about a bear ordinance, saying the town currently was looking at some model regulations.

“Quite frankly, collecting on a $10 fine is more trouble than it’s worth and would not be sufficient to compel cooperation particularly given that our worst offenders are students living off campus,” she said. “And with our relatively small staff, we simply do not have the resources to become a trash or bird feeder enforcement agency. But time will tell.”