Anaho Island NWR supports one of the two largest American white pelican nesting colonies in the western United States. On average 8,500 adult American white pelicans return to Anaho Island each spring from their wintering areas in Southern California and Baja, Mexico. These fish-eating birds rely on the spring spawning runs of Pyramid Lake fish, such as cui-ui and Lahontan cut-throat trout, as well as the numerous shallow lakes and wetlands within 70 miles of the island, primarily the Lahontan Valley and Stillwater National Wildlife Refuge. The adult pelicans often fly many miles from Anaho Island NWR and the Pyramid Lake area to forage for food, but return daily to feed their chicks. Once the chicks are able to fly, they begin to follow the adult birds to feeding areas, and by late August the birds no longer return to Anaho Island NWR. By the end of summer, about 2,900 young pelicans fledge and begin their winter migration to points south with the parent birds.
In addition to the pelicans, the most common colonial (birds in groups or colonies) nesting birds at Anaho Island NWR are Double-crested Cormorants, California gulls, and Great Blue herons. These birds spend the winter in other areas and then return to Anaho Island NWR each spring to nest and raise their young.
The island also provides year round habitat for other birds, lizards, snakes, rodents and insects. The vegetation on the island is a unique combination of native plants and non-native invasive plants, lichens, and moss, which varies from the waterline to rocky peaks as well as the west, east, and south sides of the island.
Anaho Island National Wildlife Refuge is not open to the public in order to protect this sensitive nesting habitat.