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The death of adults has very severe consequences for populations of long-lived birds, because their reproductive rates are low and parental investment in raising young is high. I Photo by J. Jeffrey) maturity, Even birds that nest and feed in wetlands are killed by cats, demonstrating that no bird in any habitat is safe from these stealthy, wide-ranging, introduced predators. Cats Carry and Transmit Diseases to Other Wildlife pese female'V areitla'). auga oaskilleyb ys 1Phoro6VKameec thair elane n /ygy„aa. phi/g sittin i&/017 marks d canoe 8 on her feral cats ? NP,S) and tracks a o io al est t a ka u t 1 me rem, -at kills Not only do cats prey on vulnerable endangered birds, but they also cavy diseases that may infect endangered birds and other wildlife. Cats are the definitive host of a potentially fatal disease called toxoplasmosis. In Hawai'i, toxoplasmosis has killed native Hawaiian birds such as the critically endangered 'alala (Corvus hawaiiensis), the endangered neni (Hawaiian goose; Branta sandvicensis), and even seabirds such as the red -footed booby (Sula sula). Because the protozoan organism that causes toxoplasmosis (Toxoplasma gondii) can complete an important part of its life cycle in seawater, this disease also poses a threat to marine mammals. Fatal toxoplasmosis was recently confirmed in an endangered Hawaiian monk seal (Mo- nachus schauinslandi), and may possibly threaten other marine mammals in Hawai'i such as the spinner dolphin (Stenella lon- girostris). In addition to threatening wildlife, toxoplasmosis is zoonotic and poses a significant health risk to pregnant women. Feral cats are also known to carry bacteria that have killed pueo (Hawaiian Short -eared Owls; Asiojlammeus sandwichensis) and 'alala. USGS Studies Ecology of Feral Cats in Subalpine Hawaii Island Feral cats now live throughout the dry subalpine and alpine shmblands of Mauna Kea and Mauna Loa on the island of Hawaii. Being completely isolated from human settlements, these cats live entirely off the land under extreme conditions, enduring freezing temperatures, battling lethal diseases, and relying entirely on hunting wildlife. Although feral cats exist in small numbers in these rugged ecosystems, they can be very damaging to endangered birds, such as the palila (Loxioides bailleui) and the 'ua'u. Understanding how feral cats live, move, and feed will allow us to formulate better strategies to protect endangered birds. The USGS has been investigating using varous oo s m- s. eluding remote cameras and telemetry. Remote Cameras Capture Images of Feral Cats Surveillance cameras installed at nests of the palila revealed that cats reduce palila nest success. Cats mainly kill palila chicks, although adult females may be killed while sitting on the nest. Cat kills at nests not being monitored by cameras are identified by hair, claw marks, and tracks around the nest. Up to I I% of palila nests are depredated by feral cats each year. These losses may threaten the survival of the species, which lays few eggs each year and takes a long time to develop to adulthood. In contrast, mainland songbirds have much larger clutches and raise nestlings much more quickly, decreasing Feral cats are difficultto study because of their nocturnal habits and wariness of people. Infrared -triggered cameras are used to determine the presence of cats in the vicinity of endangered birds.