Understanding the Ecology of Imperiled Species

Using thermal cameras, we are determining the population size and cave occupancy of the Mariana swiftlet and Pacific sheath-tailed bat. Both species face extirpation from the Northern Mariana Islands and are listed as endangered. Understanding the species' population status can assist in planning recovery efforts for both species.

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 Hawaiian Hoary Bat ( Lasiurus semotus ) or ʻōpeʻapeʻa is the only extant land mammal native to the Hawaiian archipelago and is listed as endangered due to apparent population declines, and a lack of knowledge concerning its distribution, abundance, and habitat needs. This study is designed to apply molecular techniques to document demographic information, assess genetic variability, describe...

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.

Population counts of Mariana swiftlets is critical to understand if control of brown tree snakes in Guam have aided swiftlet recovery. USGS scientists and The University of Hawai’i at Hilo are testing videographic methods to count Mariana swiftlet population size and observe their nesting and roosting behavior.

To document movement patterns and habitat use of Hawiian Hawks, GPS tags were attached to 17 individuals to track their movement across continuous, fragmented, and urban landscapes. We are now gathering multi-year tracking data to assess key aspects of habitat needs, and how these birds navigate through different ecosystems.

Many factors including habitat destruction, invasive plants, non-native predators and competitors, and introduced diseases have decimated the diverse, endemic native forest bird community of Hawai‘i. In particular, avian malaria ( Plasmodium relictum ), which is transmitted by the introduced Southern House Mosquito ( Culex quinquefasciatus ), has caused dramatic declines and extinctions in many...

Recent studies show that past and ongoing environmental changes have been substantial and have likely already affected conservation efforts in Hawai‘i. Much of the state has experienced substantial drying, including decreases in mean annual precipitation since the 1920s, longer rainless periods, and decreasing stream flow. Temperatures have been increasing in Hawai‘i for the last 40 years...

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. Demographic and ecological studies are needed to determine how...

The Hawaiian Hoary Bat ( Lasiurus cinereus semotus ) is the only extant land mammal native to the Hawaiian archipelago. It is listed as endangered due to apparent population declines, and a lack of knowledge concerning its distribution, abundance, and habitat needs. Agencies and landowners in Hawai‘i seek to assist in the creation of sustainable uses for managed lands while also protecting bat...

Loss of wetlands, invasive plants, and non-native predators pushed Hawaii’s waterbirds to the brink of extinction by the early 1900s, although population numbers have improved somewhat in recent decades with conservation efforts. Nonetheless, all Hawaiian waterbirds have global population sizes estimated around or below below 2,000 individuals, making them still highly vulnerable to extinction...

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...