NIGHTLIGHTING MINIMIZES INVESTIGATOR DISTURBANCE IN BIRD COLONIES

We used nightlighting to survey, capture, and band colonial nesting Am erican White Pelicans (Pelecanus erythrorynchos), Double-crested Cormo rants (Phalacrocorax auritus), and California Gulls (Larus californicu s) on eight nights from 1988-92 at Anaho Island National Wildlife Refu ge, Nevada. Disturbances to birds while nightlighting were minimal, an d there was no predation by gulls on eggs or chicks of other nesting c olonial birds. Territorial behavior and nest defensiveness by gulls we re less evident while nightlighting. Nightlighting was more effective for capturing young birds than for adults of most species. With adequa te preparation and proper timing, nightlighting effectively reduced th e amount of disruption to birds in nesting colonies caused by investig ators. Survival of young birds seemed unaffected by our activities.