Deaths of endangered birds highlight ‘dire feral cat issue’

Feral cats are the culprits in the deaths of a half-dozen endangered seabirds that nest on Kauai.

Last week a monitoring camera caught a feral cat dragging the body of a Hawaiian petrel from a remote breeding colony at Hono o Na Pali Natural Reserve, the Department of Land and Natural Resources said in a news release Tuesday. It was among six petrel carcasses researchers found at the reserve, which is home to several species of rare and endangered plants and animals.

Hawaiian petrels are found only in the islands, with the largest population living in the mountains of Kauai where they breed from April to December and nest in burrows. According to the news release, more than four dozen petrels have been killed by predators in the last two years at the Hono o Na Pali reserve.

Andre Raine, project coordinator for the Kauai Endangered Seabird Recovery Project, said that estimate is based on the 67 burrows being monitored by wildlife officials. He suspects the predation tally is much higher.

“This is just the tip of the iceberg” for a population “slowly but surely going down the drain,” Raine said.

Even one cat can wreak havoc on the petrels. “Feral cats are a known threat to native species all around the world and especially here on the islands,” Raine said. “They can cause widespread carnage in just a short time.”

A bird can fall prey to a cat while resting outside the burrow where it incubates a yearly egg, according to the DLNR. Burrows are typically dug a few feet below ground under native ferns or large ohia trees. Chicks are reliant on their parents, making it nearly impossible for an orphaned young petrel to survive.

Raine said cats typically eat “the meatiest parts” of the bird — the breast and back of the head — then “move on to the next one.”

The Kauai Endangered Seabird Recovery Project has employed feral cat traps, which Raine said have been successful and should be used more frequently as they are vital to seabird preservation.

However, Sheri Mann, the Kauai branch chief for the DLNR Division of Forestry and Wildlife, maintains that such predator control efforts “should be the last line of defense for these colonies.” State wildlife officials are working to protect the petrels through various management projects, such as installation of fences to keep predators away.

In the DLNR release, Mann said, “The fact that we have cats slipping through highlights how dire the feral cat issue is on Kauai and that control efforts solely in wilderness areas are not enough to fully deal with this problem.” She added, “It will take a concerted effort by the island community as a whole to protect native species.”

Raine said residents statewide can do their part to help halt plummeting population numbers by keeping cats indoors and refraining from feeding feral cats.

“This happens all the time to all native plants and animals and it’s not just restricted to one place and time,” he said. “We all need to know that this is a serious conservation effort and be aware of the threat that cats pose.”

Dogs can pose a threat, too. Last month, 34 Newell shearwater birds were attacked and killed on Kauai’s south coast. In that case, dogs and their owners are being blamed.

In response to that incident, a DLNR news release noted “multiple attacks on Kauai’s native birds by dogs and cats over the years” and urged residents to ensure that dogs are not allowed to run loose, which is a violation of both state and county laws.