Feral dogs attacked a nesting colony of wedge-tailed shearwaters at Ka'ena Point Natural Area Reserve Sunday night, killing 21 chicks as they sat in their burrows.

"This is the reason dogs are strictly prohibited in the reserve, and this is clearly marked on information signs at entry points," said Peter Young, chairman of the state Department of Land and Natural Resources. "However, some people are still being seen bringing their dogs there, and homeless persons in nearby communities may be allowing their dogs to run loose — a practice that once again has had tragic and devastating results."

Wedge-tailed shearwaters are ground-nesting birds that prefer coastlines. Their cousins the Newell's shearwaters nest in burrows in mountains. The first of more than 700 chicks in the Ka'ena colony were expected to make their first flights during the coming week. The reserve is also home to Laysan albatross.

The birds are vulnerable to dogs, cats and mongooses. In normal years, predators kill as many as 40 percent of the chicks.

Land department contract workers reported several dogs loose in the Ka'ena area the morning after the chicks were killed.

"Since 1994, DLNR has been tracking seabird populations at Ka'ena Point, and actively managing this area with vegetation restoration efforts, a low-intensity predator control program, and the restriction of vehicle access to the reserve," Young said.

Young said the department will try to remove the dogs from the colony, and will try to determine how they got into the area.

"Pets that are abandoned or left to run loose in a Hawaiian ecosystem become predators, with catastrophic results," Young said. "We provide signs that warn people not to take or introduce pets into protected areas. If we find animals that are pets, we try to capture and remove them, and inform any owners about violation of our rules and the damage that stray or abandoned pets can cause."