Factors influencing Imperiled Species Populations

USGS researchers are combatting avian malaria by improving the trapping and tracking of mosquitoes in endangered Hawaiian bird habitats.

Abundance data are collected for bird populations throughout the Pacific Islands by numerous federal, state, university, and non-profit organizations. In order to ensure data are standardized and available to researchers throughout the region, interagency bird databases have been created and continue to be used. These databases contain more than a million compiled, proofed, and standardized...

The brown treesnake is an invasive species that decimated many of Guam’s native vertebrate species. Under the leadership of the Pacific Island Ecosystems Research Center (Hawaii) and co-located with U.S. Fish and Wildlife Service at the Guam National Wildlife Refuge, the brown treesnake team works to prevent snakes spreading to other islands, develop and test tools for control efforts on Guam, and...

Many of Hawai‘i’s forest birds have shown significant declines in the past 200 years, with many currently listed as endangered species. Multiple threats have been identified as contributing to declines, including disease, invasive species, habitat loss, and decreased survivorship and productivity caused by introduced predators. Through a combination of demographic information, population modeling...

We are sequencing the DNA of Wolbachia bacteria found in mosquito populations in Hawai’i and those used for mosquito control. We are also developing sample processing techniques to increase the efficiency and accuracy of monitoring mosquito control efforts to help long-term survival and restoration of Hawaiian forest bird populations.

While the Hawaiian avian disease system has been well-studied in the forests of the older section of Hawai‘i Volcanoes National Park (HAVO), and in many other locations throughout the state, nothing was known about avian disease in the new Kahuku Unit of HAVO and the adjacent Ka‘u Forest Reserve. The high elevation forests of Kahuku are the only habitat located on National Park Service lands where...

Both wildlife and human health in Hawai‘i and other island ecosystems in the Pacific Basin face continued threats from introductions of diseases and vectors. Accidental introduction of mosquito-borne avian malaria and pox virus to Hawai‘i is an outstanding example of how biological invasions can have a profound effect on endemic wildlife. The geographic distribution, density, and community...

USGS and Oregon State University (OSU) have joined forces to support USFWS with research needed help manage and recover the endangered Hawaiian duck, locally known as koloa maoli. Hybridization of koloa with feral Mallards on O‘ahu and Maui is believed to have resulted in complete introgression in those populations (Engilis et al. 2002), and Kaua‘i is the only island that likely supports a viable...

The federally endangered nēnē, or Hawaiian Goose, once present on most of the Hawaiian Islands, was found only on Hawai‘i Island by 1900. This remnant population was reduced to as few as 30 individuals by 1952 due to the combination of unregulated hunting, introduced mammalian predators, and large-scale habitat degradation. Nēnē have been restored to a few places like Hawai‘i Volcanoes National...

The palila is an endangered species of Hawaiian honeycreeper which exists only in subalpine forests dominated by māmane and naio on Mauna Kea Volcano. The diet of this finch-billed bird is unusually restricted; immature seeds, flowers, and insects found on māmane trees are critical to its existence. Māmane also is the preferred nesting substrate of the palila. Federal court orders have resulted in...

This project examined altitudinal movements of the endangered Hawaiian hoary bat and their use of high elevation caves on the slopes of Mauna Loa volcano on the island of Hawai‘i.

The Samoan swallowtail is a large and strikingly marked butterfly endemic to the Samoan Archipelago. Once widespread and common, its populations have declined dramatically. The Samoan swallowtail is a possible candidate as an indicator of ecosystem health for this oceanic island ecosystem.