Birding In The National Parks: Petrels And Cats Don't Mix At Hawai'i Volcanoes National Park

Hawaiian petrels are being devoured by feral cats at Hawai'i Volcanoes National Park. Hawaiian Petrel and egg by Kauai Endangered Seabird Recovery Project.

I love cats. I have a cat myself and he’s part of my family. I also love wildlife, and there is now ever-increasing evidence that outdoor cats and wildlife – birds in particular – do not mix well. Feral and outdoor cats are notorious for being efficient hunters, as shown by the well-known “kitty cam” study in Georgia. Now, the latest bad news about feral cats is from Hawai’i, home of some of the most endangered birds on the planet.

It has long been assumed that feral cats are a significant factor in the decline of the endangered Hawaiian Petrel. Petrels are seabirds that spend the vast majority of their lives on the ocean, but the brief time they spend on the Hawaiian islands is their nesting and rearing period, clearly the most crucial part of the year for the population.

In a study based partly on Mauna Loa in Hawai’i Volcanoes National Park and funded by the National Park Service, University of Hawai’i, and U.S. Geological Survey, cameras were stationed for the monitoring of Hawaiian Petrel nest burrows. Evidence from bird carcasses and cat stomach contents has confirmed that cats are consuming petrels, with the assumption being that they are taking live parts rather than scavenging for carrion. This study monitored 14 burrows and caught cats frequenting eight of them, including video evidence of one cat waiting at a burrow for an hour for a chick to emerge and then quickly dispatching the young bird.

While predation on chicks of endangered birds is obviously detrimental, the taking of reproductive adults could have even greater consequences.

“This species has delayed sexual maturity, low reproductive potential, and extended nesting development, all of which place a premium on survivorship of the adult birds. Further, the birds also have a high degree of mate fidelity and may have difficulty replacing mates that have been depredated,” said Dr. Darcy Hu of the National Park Service.

The National Park Service is taking steps to protect Mauna Loa’s petrel nests. With support from the U.S. Fish and Wildlife Service, National Fish and Wildlife Foundation, and the American Bird Conservancy, the National Park Service is constructing a fence specially designed to keep cats and mongooses out of nesting areas. Six-hundred-and-forty acres of habitat and about 45 active petrel nests will be protected by the fence.

The moral of this story is simple: Spay and neuter your cats and keep them indoors. Even some of the most remote parks and refuges have populations of feral cats now that all began with seemingly harmless releases and continued care of urban feral cat populations. Let’s enjoy our feline companions in our homes so that we can continue to enjoy our avian friends in the wild.