Feral Cats Still a Threat to Endangered Seabirds

A feral cat caught caught by a night-vision camera is seen here dragging a seabird. Photo courtesy of DLNR.

Researchers discovered the bodies of six endangered Hawaiian Petrels at a remote breeding colony in Hono o Na Pali Natural Area Reserve, Kaua‘i two weeks ago. All had been dragged from their breeding burrows by feral cats and partially eaten, including one incident that was caught on a monitoring camera, according to a state Department of Land and Natural Resources press release.

“Unfortunately these incidents continue to happen with regularity on Kaua‘i,” said Dr André Raine, Project Co-ordinator for the Kaua‘i Endangered Seabird Recovery Project. “Feral cats are found all over our islands, even in the most remote and inaccessible regions. They are a significant threat to not only native seabirds, but a wide range of other endangered bird species.”

The Hawaiian Petrel is an endangered seabird found only in the Hawaiian Islands. Its populations have declined dramatically in recent years on Kaua‘i, where it faces a number of threats including being eaten by introduced predators such as cats. Several colonies of these birds are now being protected by seabird management projects, which include the control of introduced predators.

“Introduced predator control projects are a vital part of seabird management, and have successfully decreased the number of introduced predators in remote seabird colonies in recent years” explained Dr Raine. “However, as this incident shows, it only takes one cat to get into a colony, where it can then kill a large number of nesting birds in a very short period of time.”

Sheri Mann, the Kaua‘i Branch Chief for the DLNR Division of Forestry and Wildlife, said predator control efforts should be the last line of defense for these colonies.

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

Hawaiian Petrels come to Kaua‘i to breed from April to December and nest in burrows which they dig in the ground under native ferns and at the base of large trees such as ‘ohi‘a. At this time of year, they are incubating a single egg, and are extremely vulnerable to cats and other predators who can get into burrows to kill them.

“In the last two years, we have found the bodies of at least 48 endangered seabirds that were killed by feral cats and this represents just the tip of the iceberg,” Raine said. “If we continue to have large numbers of feral cats roaming the landscape, the situation will only deteriorate for these beautiful and iconic birds. We can all help by encouraging responsible pet ownership, which includes keeping cats indoors and away from our native wildlife.”