Feral cats have inhabited Hawaiian forests since soon after their introduction in the late 1700s, contributing to the decline and extinction of native birds. Effective control strategies require data on population dynamics, but little is known about the cats’ annual or lifetime survival rates.
Researchers associated with UH’s Hawaiʻi Cooperative Studies Unit, state Department of Land and Natural Resources and the U.S. Geological Survey trapped cats at two woodland sites on the west and north slopes of Mauna Kea designated as critical habitats for the endangered Hawaiian honeycreeper.
Analyzing teeth to determine age distribution, they calculated an average annual survival rate of 0.647 for cats age 1 or older. Nearly 15 percent of females were pregnant; 37 percent had antibodies to Toxoplasma gondii and 7 percent were infected with the parasite.
Writing in the July issue of Pacific Science, the scientists note that a long-lived cat is capable of substantial predation over its lifetime; has a greater chance of transmitting the parasite, which can kill native species; and can contribute to rapid population rebound after control efforts.