Pilot Hi-Tech Study Searches for Rare Hawaiian Birds

Hawaiian Petrel. Photo: USFWS

Detecting rare Hawaiian birds using conventional methods is difficult due to the rough, mountainous terrain, dense vegetation, and remote locations of intact Hawaiian rainforests. American Bird Conservancy and the Conservation Endowment Fund of the Association of Zoos and Aquariums are supporting Hawaiian partners on the island of Kauai in a pilot study to determine the feasibility of using Autonomous Recording Units (ARUs) to detect rare bird species. ARUs are small, battery-powered recording devices containing a microphone, software, and built-in disk drive that turn on automatically to record bird calls. The devices are very low-maintenance, can sit unattended for weeks or even months, and collect up to 80 gigabytes of digital recordings.

Although ARUs are a relatively new technology, they have already been successfully used to monitor Golden-cheeked Warblers and Black-capped Vireos at Fort Hood, Texas, in areas where military exercises would pose a threat to researchers. ARUs are also being deployed in Arkansas to search for the Ivory-billed Woodpecker.

Two ARUs have been leased from the Cornell Lab of Ornithology, and are being field tested by the Kauai Endangered Forest Bird Recovery Project and the Kauai Endangered Seabird Recovery Project. The study is funded and directed by the Hawaii Division of Forestry and Wildlife. ARUs have been deployed in four different areas on Kauai in an attempt to detect four species: the Hawaiian Petrel, Newell’s Shearwater, Band-rumped Storm-Petrel, and Puaiohi (Small Kauai Thrush).

Because of the difficulty of accessing some research locations on Kauai, use of ARUs could save thousands of dollars in helicopter transport charges and study time. ARUs will also help in better understanding the singing and calling behavior of Hawaiian landbirds, allowing researchers to fine-tune monitoring protocols to increase native bird detection success. ARUs could also help detect cryptic species—perhaps even species that have not been reported for years.

Once the field portion of the study ended in August, the ARUs were sent back to Cornell, where the data will be analyzed and the quality of the sound evaluated. “ARUs have tremendous promise for monitoring rare Hawaiian species while saving time and money in areas with very challenging logistics,” said George Wallace, American Bird Conservancy’s Vice President for International Programs. “We eagerly await the results of the pilot study.”