Deadly Avian Predator Confirmed on Kaua’i, Hawai’i

A deadly predator of birds – a mongoose (Herpestes javanicus) – has been captured on the Hawaiian Island of Kauaʻi, confirming the worst fears of local wildlife officials. Previously, Kauaʻi and Lanaʻi were believed to be the only two Hawaiian Islands free of non-native mongooses that prey on native birds. Mongoose predation has been a major factor in bird population declines in the archipelago, which has been dubbed “the bird extinction capital of the world.”

Mongooses were first released on several islands in Hawaiʻi in the late 1800s as part of an unsuccessful attempt to control rat populations in the sugar cane fields. While mongooses did kill some rats, they are largely diurnal while rats are more nocturnal, and hence the mongooses turned to other sources of food for their survival, in particular, birds.

“Mongooses eat ground-nesting bird eggs as well as chicks. Their prior absence on Kauaʻi was a major reason why populations of the state bird, the Nēnē, have been able to do so well there,” said Dr. George Wallace, Vice-President for Oceans and Islands for American Bird Conservancy (ABC). “Without question, the confirmation of mongoose on Kauaʻi is very bad news for several remaining endangered bird species on the island.”

Local officials had received more than 70 reports of sightings of mongoose on Kauaʻi over the last ten years, but until now, a live mongoose had never been captured, despite trapping programs by the Kaua‘i Invasive Species Committee (KISC), the Division of Forestry and Wildlife, and the U.S. Department of Agriculture. The capture was made on May 2 by KISC staff, but sighting reports continue to be received, implying that other mongooses are present. Local, state, and federal agencies are now collaborating on a plan to deal with the mongoose.

The shocking extent of the decline of native bird populations in the Aloha State was recently documented in a 30-minute film by ABC entitled Endangered Hawai’i. Since the arrival of Europeans to the Hawaiian Islands, 71 bird species have become extinct out of a total of 113 endemic species that existed at the time of first human colonization. Of the remaining 42 species, 32 are federally listed, and ten of those have not even been seen for up to 40 years.

“No place else on Earth has witnessed the levels of bird extinctions that we have seen in our 50th state,” Wallace said.

The film points out that the primary threats to Hawaiian birds are exotic species: predators such as mongoose, feral cats, and rats; herbivores such as goats and pigs that degrade native habitat; diseases such as avian malaria and pox transmitted by non-native mosquitoes; and plants that displace native species and reduce habitat quality for native birds. Climate change may further reduce or eliminate mosquito-free – and hence disease-free – upland habitat as temperatures rise.

The film says that significant federal funding is the key to reversing current. Unfortunately, the resources directed to Hawaiʻi’s environmental problems are alarmingly low in proportion to their need. While Hawaiian birds comprise one third of all U.S. bird species listed under the Endangered Species Act, only 4.1% of funding for recovery of listed bird species is directed their way.

The film can be watched below.