Nesting Ecology and Production of Western Grebes at Bear River Migratory Bird Refuge, Utah

Abstract

The nesting ecology of Western Grebes (Aechmophorus occidentalis) was studied at Bear River Migratory Bird Refuge, Utah, in 1973 and 1974. Western Grebes nested on dry land, emergent vegetation, and in open-water areas in colonies and single nests. They selected sites near open water (approximately 30 cm in depth). At least one young hatched in 21% of the nests. Avian predation and abandonment of nests caused the largest losses. Mated pairs produced an average of 1.7 young.