KILAUEA, Kaua'i — At least two dogs sneaked into a protected nesting area for gooney birds on Kaua'i and killed 15 of them.

Officials believe that the dogs infiltrated Na Aina Kai Tropical Botanical Gardens on Tuesday night through a hole in a fence opened by beachgoers seeking a shortcut.

A small colony of gooney birds — as species also known as the Laysan albatross — has been nesting for several years on the grounds of the private, nonprofit organization. The U.S. Fish and Wildlife Service built a fence around the colony to protect it.

The Laysan albatross is not endangered but the species is protected under the Migratory Bird Treaty Act. A dog owner whose pet kills one of the sea birds faces up to $5,000 in fines and six months in jail.

Brenda Zaun, a biologist for the U.S. Fish and Wildlife Service, said the loss of 15 birds is serious considering that only 200 pairs nest per year.

But she was perhaps most upset that people made a hole in the fence.

"The end of the fence had been pulled back by people trespassing onto that property from the beachside," she said. "When trespassers cut a fence, it also allows predators a way in. The trespassers are just as much at fault as the dog owner."

Kapa'a resident Richard Spacer witnessed at least part of the attack after watching two mid-sized dogs — one cream-colored with a black collar and another with a black coat — circling the protective fence.

"The light-colored dog killed a good-sized albatross; he was thrashing it around, then the black got ahold of one," Spacer said Wednesday after he reported the incident. "It was very disgusting."

Zaun said sea birds aren't used to defending themselves against mammal predators. She said they don't have the instinct to fight or fly away because they believe they're safe on land.

Dogs have killed the sea birds on Kaua'i before, including an incident two years ago in which dogs killed eight chicks and six adults.

In January of 2005, federal officials fined a Kilauea resident more than $2,000 when her two dogs allegedly killed 27 albatrosses at Kepuhi Point.

Zaun encouraged those who see dogs harming wildlife to report it immediately and interfere if they can.

"Sometimes just yelling at dogs will cause them to stop and run away," she said.

Taking pictures and remembering descriptions will also be helpful in tracking down the owners.

The Laysan albatross, which has a wingspan of 6 to 7 feet, is Hawai'i's largest sea bird.