The Behavior And Relationships Of The Least Grebe

Abstract

The Least Grebe, Tachybaptus dominicus, is widely distributed in the warm parts of the New World. It feeds on a wide variety of animals, including dragonflies and ants, the latter taken fro emergent vegetation. Reverse mounting and copulation were filmed and analyzed. The former differed from the latter in that there was no cloacal contact and the series of postmounting displays was less regular in timing and in alternation between members of the pair. The posture of the head in inviting differed from that of other grebes. No rearing or wing-quivering was observed. Four calls are described and the contexts in which they were used are discussed. The Least Grebe resembles the Old World lettle grebes, Tachybaptus ruficollis and T. novaehollandiae, in its cryptic resting posture, duet trells, and general habits; and it is probably more closely related to them than to any other grebes.