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 Figure 1. Akikiki juveniles have “spectacles” and will retain the dull pink bill into maturity. Photo by Jack Jeffrey INTRODUCTION The remote montane rainforests of the Alakai plateau, Kauai, are the only remaining habitat for nearly all of the island’s native forest birds. Habitat loss and degradation, introduced mammalian predators, and introduced avian diseases have all contributed to the decline and gradual retreat of forest birds to higher elevations. Declining bird populations continued to suffer severe losses on Kauai from hurricanes in 1982 and 1992. The Akikiki (Oreomystis bairdi) or Kauai Creeper (Fig. 1) has undergone a contraction in range and a decrease in abundance over the last 30 years. However, lack of quantitative data covering the species’ entire range has hindered our ability to assess the extent of the decline. This poster presents the results of the first systematic study covering the entire range of the Akikiki since surveys conducted by John Sincock in 1968-73. These data are presented in an effort to facilitate decisions on the listing and recovery planning of Akikiki.  Figure 2. The Alakai plateau is a relatively intact montane forest ecosystem receiving 2,000 to 11,000mm of annual rainfall.  Figure 3. Akikiki detections from March 2000. The red area highlights the range of Akikiki determined by John Sincock from 1968-74 surveys, and the black dotted area is the current estimated range from BRD 2000 surveys. METHODS The Alakai swamp is situated on a plateau between 1000 and 1300m (Fig. 2) on Kauai Island, Hawaiian Archipelago (Fig. 3). We established and surveyed the 6 original Hawaii Forest Bird Survey (HFBS) transects and an additional 28 new transects across the Alakai plateau and adjacent forest in the Kokee region in March 2000. We surveyed 552 stations on 34 transects. Survey stations were 150m apart, a total survey distance of 77 linear kilometers. To increase the likelihood of detecting rare species, the majority of stations (75%) were surveyed at least twice. Variable circular-plot (VCP) methodology was employed, and we used multiple linear regression to account for the effects of covariables on detection distance. The effective detection radius (EDR) was then calculated using DISTANCE (Reynolds et al. 1980, Buckland et al. 1993, Fancy 1997). We did not pool species detections among years when calculating EDRs because of the forest destruction from 2 hurricanes and subsequent forest regeneration likely influenced bird detectability among years. EDRs ranged from 23.3 - 27.1m.  Figure 4. Density estimates for the HFBS (25 km²) study area. Surveys in 1981 did not include two transects on private land that were included in 1989, 1994, and 2000. RESULTS • There was no significant change in Akikiki densities in the southeast Alakai plateau (25km²), the area of highest densities, among the sampling years in 1981, 89, and 94. However, Akikiki densities declined significantly (86%) between 1994 and 2000, from a mean of 182 birds/km² to 44 birds/km² (Fig. 4). • Akikiki’s range has decreased an estimated 28% since 1973 (Fig. 3 and 5). • The overall population of Akikiki decreased approximately 36% from 6800 (± 1900 SE) (Sincock et al. 1984) to 2448 (± 1200 SE) in 2000 (Fig. 5). *These are preliminary estimates and final assessments will be based on analysis of habitat suitability maps.  Figure 5. Overall population estimates for 1968-73 in the larger range (87 km²) from Sincock’s data based on 627 1/2 counts; and for the estimated retracted range (63 km²) from BRD 2000 data based 552 stations using VCP methodology. DISCUSSION The Akikiki was noted as more abundant in the 1960s than two of the region’s most common species, the Kauai Amakihi (Hemignathus kauaiensis) and Anianiau (Viridonia parva) (Richardson and Bowles 1964). The HFBS reported Akikiki still common in 1981 (Scott el al. 1986). Currently Akikiki are rare and densities are significantly lower in these same areas. The overall population of the species has declined approximately 36%, and range has contracted 28%. Six critically endangered bird species occur in the Alakai, however, we did not detect the Akiakloa (Hemignathus obscurus), Kamao (Myadestes myadestinus), Nukupuu (Hemignathus lucidus), Kauai Oo (Moho braccatus), or Ou (Psittirostra psittacea). Their continued existence is questionable. To date, it appears that we missed the opportunity for an active recovery program on these 5 species. The Akikiki is a candidate for the Endangered Species list, and our preliminary results support listing this species. Our understanding of Akikiki demography and ecology is insufficient, with only 7 nests documented. Comprehensive data on the basic biology of Akikiki will be necessary for developing recovery plans and species preservation. LITERATURE CITED Buckland, S.T., D.R. Anderson, K.P. Burnham, and J.L. Laake. 1993. Distance sampling: Estimating abundance of biological populations. Chapman & Hall, New York. Fancy, S.G. 1997. A new approach for analyzing bird densities from variable circular-plot counts. Pacific Science 51:107-114. Reynolds, R.T., J.M. Scott, and R. A. Nussbaum. 1980. A variable circular-plot method for estimating bird numbers. Condor 82:309-313. Richardson, F., and J. Bowles. 1964. A survey of the birds of Kauai, Hawaii. Bernice P. Bishop Mus. Bull. 227: 1-51. Scott, J.M., S. Mountainspring, F.L. Ramsey, and C.B. Kepler. 1986. Forest bird communities of the Hawaiian Islands: their dynamics, ecology, and conservation. Stud. Avian Biol. No. 9. Sincock, J.L., R.E. Daehler, T. Telfer, and D.H. Woodside. 1984. Kauai forest bird recovery plan. U.S. Fish and Wildlife Service, Portland, OR. ACKNOWLEDGEMENTS SURVEYORS Corey Adler, Rick Camp, Jim Denny, Jeff Foster, Jack Jeffrey, Glenn Klingler, Thomas Kaiakapu, Jay Nelson, Thane Pratt, Al Silva, Tom Telfer, and Erik Tweed HAWAII DEPARTMENT OF LAND AND NATURAL RESOURCES - DIVISION OF FORESTRY AND WILDLIFE Paul Conry and Ed Petteys HAWAII DIVISION OF STATE PARKS Wayne Souza KOKEE NATURAL HISTORY MUSEUM Marsha Erickson and Michelle Hookano |
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