Status of the White-faced Ibis: Breeding colony dynamics of the Great Basin population, 1985-1997

The status of the White-faced Ibis (Plegadis chiki) in the Great Basin is o f concern because of its small population size and the limited and dynamic nature of its breeding habitat. We analyzed existing annual surrey data for the White-faced Ibis breeding in the Great Basin and surrounding area for 1985-1997. Methods varied among colonies and included flight-line counts an d fixed-wing aircraft and helicopter surveys. The number of White-faced Ibi s bleeding pain in the Gt eat Basin area has nearly tripled since 1985, des pite years of severe flooding and drought at major breeding areas. This gro wth is reflected in both peripheral (i.e., Oregon, California, Idaho) and c ore (i.e., Nevada and Utah) components of the population. Our data on colon y dynamics in Oregon and Nevada illustrate the ability of the highly nomadi c White-faced Ibis to compensate for poor conditions at traditional colony sites by moving among colonies and rapidly colonizing newly available wetla nds. We suggest that the White-faced Ibis would benefit from a landscape mo saic of well-distributed peripheral wetlands and persistent colony sites. T he nomadic nature of the White-faced Ibis and the dynamic nature of their b reeding habitat necessitates that wetland management decisions and populati on monitoring be conducted in a regional context.