KAUAI BIRD SPECIES

Distribution, Status, and Trends of Kauai Bird Species of Special Concern

Pacific Island Ecosystems Research Center, Biological Resources Division, USGS
Principle Investigator: B. L. Woodworth
Project Coordinator: Jeffrey Foster
Ornithological Assistants: Erik J. Tweed, Corey Adler

As late as 1969, Kauai still possessed all of its historically-known forest birds. Since then, five species, the Ou (Psittirostra psittacea), Kauai Oo (Moho braccatus), Kamao (Myadestes myadestinus), Kauai Nukupuu (Hemignathus lucidus hanapepe), and Greater Akialoa (Hemignathus ellisianus), have been reduced to extremely low numbers and may be extinct. One endangered species, the Puaiohi (Myadestes palmeri) and four bird species of special concern still remain in the forest of Kauai: the Akikiki (Oreomystis bairdi), Akekee (Loxops caeruleirostris), Anianiau (Hemignathus parvus), and Iiwi (Vestiaria coccinea).
     The Akikiki is a Hawaiian honeycreeper endemic to the island of Kauai and currently restricted to the montane plateau of the Alakai Wilderness Preserve. Noted as abundant in 1960, Akikiki have shown a precipitous decline in their numbers the past 40 years and a gradual contraction in range. The contraction of the Akikiki's range, first noticed in the Kokee region along the western periphery, closely mirrors the pattern of decline seen for other critically endangered species on Kauai. Although limiting factors for Akikiki are unknown, avian disease, introduced mammalian predators, habitat degradation due to invasive plants and feral ungulates, and two recent hurricanes are all likely to have contributed to its decline.
      The last comprehensive survey of forest birds on Kauai was conducted from 1968-1973 (Sincock et al. 1984; Figure 1). In 1981, the USFWS (now BRD) conducted systematic surveys in a portion of the area as part of the Hawaii Forest Bird Survey (HFBS) (Scott et al. 1986), and these surveys were repeated in 1985, 1989, and 1994 (Figure 2). However, these surveys covered only about a quarter of the good-quality high-elevation habitat remaining in the States Alakai Wilderness Preserve. The rapid pace of ecosystem change and invasive species introductions in Hawaii, along with two major hurricanes impacting Kauai in the past 10 years, have rendered the original range-wide surveys (which were of limited resolution to begin with) inaccurate and outdated. Furthermore, state survey data have not been fully analyzed, impeding our ability to make comparisons of the historic transects over time. The current project proposes to conduct systematic surveys of the birds of special concern for the island of Kauai, including the Akekeke, Akikiki, AniAniau, and Iiwi. In particular, this project will provide updated population status and distribution of Kauais forest bird species of special concern, for use in listing decision, recovery plan development, and funding allocation decisions.
     In March 2000, the Biological Resources Division - USGS, in cooperation with Hawaii Division of Forestry and Wildlife and the U.S. Fish and Wildlife Service, conducted the first-systematic survey of forest bird populations throughout the Alakai region since John Sincocks 1968-1973 surveys. A total of 34 transects were surveyed using standard VCP methodology, including over 77 linear kilometers and 550 point count stations covering approximately 100 km² of the Alakai region, were surveyed (Figure 3). The surveys included the majority of intact native forest on Kauai above about 1200 m. Preliminary population estimates and trends for Kauai species of special concern have been determined, and results presented at three professional meetings and in a manuscript (in prep). In addition, we are currently developing (in collaboration with the Hawaii Forest Bird Interagency Database Project) methods for modeling species-habitat relationships to better understand population trends and distribution of the species of concern. The current project will provide updated population status and distribution of Kauais forest bird species of special concern, for use in listing decision, recovery plan development, and funding allocation decisions.

Publications in progress:
1. Foster, J. T., E. J. Tweed, B. L. Woodworth, and R. Camp. Avian Population Trends in the Alakai Swamp, Kauai: Native Declines and Exotic Expansions? Foster, J. T., E. J.

Technical Reports:

1. Woodworth, B.L., J. T. Foster, E. J. Tweed, and R. Camp. Distribution, Status, and Population Trends of Kauai Bird Species of Special Concern. Report to U.S. Fish and Wildlife Service. Pacific Island Ecosystems Research Center, USGS-BRD. (in prep).

Presentations:
1. Avian Population Trends in the Alakai Swamp, Kauai: Native Declines and Exotic Expansions? 2001 Annual meeting of the Society for Conservation Biology, Hilo, HI.
2. Population status and distribution of the Akikiki, a Kauai bird species of special concern. Poster presentation to 2000 Hawaii Conservation Conference, Honolulu, HI.
3. Avian Population Trends in the Alakai Swamp, Kauai: Native Declines and Exotic Expansions? 2001 Annual Meeting of the American Ornithologists Union, Seattle, WA.