Pacific Island Ecosystems Research Center
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| 1 Pacific Islands Ecosystem Research Center USGS- Biological Resources Division P.O. Box 44 Hawaii National Park, HI 96718 |
2 USFWS, Pacific Remote Islands NWR Complex P.O. Box 50167 Honolulu, HI 96850 |
| The last wild population of Hawaii's endemic Laysan duck (Anas laysanesis) exists on Laysan Island, Hawaiian Islands National Wildlife Refuge. Laysan Island's ducks are a relict population and at high risk of extinction due to severe weather, disease, accidental introductions, and habitat degradation. |  Morphometrics |
| An alarming population decline occurred on Laysan in 1993. Poor recruitment in 1998 (n = 4 fledglings) was due to starvation, and parasite infestation of limited water sources by the nematode, Echinuria uncinata. Drought conditions during El Ninos and alien insects, including bigheaded ants (Pheidole megacephala) are suspected of reducing the duck's food abundance. The Lincoln-Petersen Index was used to estimate population size from mark recapture and resight data. We estimate the 1999 adult population is 322 ducks (95% C.I. 290 to 355). On going population dynamics and foraging ecology research will be applied to restoration and conservation planning for Laysan Island and Anas laysanesis. |  Night Measure |
| The Laysan Duck Project is a cooperative project of the U.S. Fish and Wildlife Service, USGS BRD, and the Virginia Polytechnic Institute and State University. New project supporters for 1999 include Duck's Unlimited Hawaii, Inc., and the National Geographic Society's Committee for Research and Exploration. |  Laysan Island |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://biology.usgs.gov/pierc/
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