A young bear fell through an Alaska couple's skylight while they were preparing to celebrate their child's birthday, forcing them to flee the room while he gorged on cupcakes.

A wildlife management coordinator said yesterday that the bear is believed to have been a juvenile male weighing about 82 kilograms.

"There probably isn't a neighbourhood or place where we have homes where the potential isn't there for you to run into a bear or observe a bear," said Ryan Scott of the Alaska Department of Fish and Game. "There is really no place where the potential isn't there."

The couple's home is situated close to a mountainside that overlooks downtown Juneau, Alaska and Scott said those types of neighbourhoods closer to trees were more likely to see more bears. "Bears are extremely curious and will stake out any source of food they can find," he said.

The home owners, Alicia Bishop and Glenn Merrill, told the Juneau Empire that the bear landed in their living room.

"I was literally in the room, and I heard this cracking," Merrill told the paper, describing the sound of the skylight's plexiglass creaking under the bear. "And the next thing you know, there's this bear that, I mean, literally, fell right from (the skylight). It was like one metre away from me."

Bishop explained that she opened a door from the living room that led to the backyard and that the couple yelled at the animal until it casually walked out of their residence.

Juneau police officers had to kill the juvenile male, because it posed a threat to human life, according to Scott.

"We don't take killing or destroying bears lightly," the Fish and Game official added. "People were inside that building. I think it was appropriate for that given the situation."