Providing evidence to improve practice

Individual study: Provision of wetlands for Hawaiian duck Anas wyvilliana in the Kohala and Mauna Kea regions of the Island of Hawai'i, Hawaii, USA

Published source details

Uyehara K.J., Engilis A. Jr. & Dugger B.D. (2008) Wetland features that influence occupancy by the endangered Hawaiian duck. Wilson Journal of Ornithology, 120, 311-319


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Restore or create inland wetlands Bird Conservation

A replicated, site comparison study from March 2002 to July 2003 in wetlands in Kohala-Mauna Kea, Hawai’i (Uyehara et al. 2008) found that Hawaiian ducks Anas wyvilliana used 16 restored wetlands more often than 32 agricultural wetlands, despite the greater availability of the latter. Restored wetlands had a significantly higher occupancy rate than agricultural wetlands (81 vs. 41% of sampled sites) and higher consistency of occupancy (13 vs. 7% of all surveys). Hawaiian ducks preferred wetlands that were larger (>0.23 ha), further from houses and surrounded by more wetland habitat. No wetland within 600 m of a house was occupied. Wetland occupancy was not affected by presence of invasive species or grazing intensity. Wetlands ranged from 0.01-1.30 ha and were surveyed every two months.