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Andrew Engilis

Publications and source records attributed to Andrew Engilis.

2 recordsLinked to original sources
USGS2007

Hawaiian Duck's Future Threatened by Feral Mallards

Nearly 70 percent of Hawaii's native bird species are found nowhere else on Earth, and many of these species are declining or in danger of extinction. Although the Hawaiian Islands were once home to a remarkable diversity of waterfowl, only three species remain-the Hawaiian Goose (Nene), Laysan Duck, and Hawaiian Duck (Koloa maoli)-all Federally endangered. The Koloa maoli is the only Hawaiian bird threatened by 'genetic extinction' from hybridization with an invasive species-feral Mallard ducks. U.S. Geological Survey (USGS) biologists in Hawaii are working to find the causes of bird endangerment and ways to prevent extinction of the Koloa maoli and other threatened birds.

Fact Sheet↗
USGS1993

Status and population trends of Hawaii's native waterbirds, 1977-1987

Status and population trends of Hawaiis ’ native waterbirds were examined from 1977 through 1987. Waterbird population fluctuations were analyzed in relation to rainfall and land use dynamics. Numbers of Hawaiian Duck (Koloa) ( Anus wyvilliana ) and Hawaiian Common Moorhen ( Gallinula chloropus sandvicensis ) appeared stable over time; however, surveys were limited. Increase in Black-crowned Night-Heron ( Nycticorux nycticorux ) abundance appeared linked to expansion of aquaculture, particularly on Oahu, and not to climatic events. Annual rainfall patterns help explain and predict population fluctuations and anomalous distribution patterns involving Hawaiian American Coots ( Fulica americana alai ), moorhens, and Hawaiian Black-necked Stilts ( Himantopus mexicanus knudseni ). Coot, stilt, and moorhen populations fluctuated with climatic events, and intraisland dispersal to ephemeral wetlands occurred. Stilts exhibited regular inter-island migratory behavior, but coots dispersed in relation to major rainfall events. Seasonal fluctuation recorded for coots by past observers is the result of survey techniques not accounting for seasonal dispersal patterns.

Hawai'i↗