Displays, Vocalizations and Breeding Biology of the Great Grebe (Podiceps major)

Abstract

-In studying the Great Grebe (Podiceps major) in Chile, I identified 14 displays and 8 adult vocalizations. The courtship displays were performed throughout the year, indicating maintenance of the pair bond after nesting ends, and suggesting that the grebes form long-term pairs. Breeding was not confined to any season; pair bond maintenance may be an adaptation that permits reproduction whenever environmental conditions are favorable. The mutual courtship displays--displays performed only by two grebes-were performed in significantly more ceremonies than were certain courtship displays performed by individuals. Shaking the closed wings during the rearing display was associated with copulation. The number of eggs on a nest platform was positively correlated with the degree to which the grebe covered the eggs with vegetation before leaving the nest. Both adults cared for the young, in some cases until the young were fully