Both males and females of many avian species maintain elaborate plumage traits, and elaborate monomorphic plumage may convey
adaptive benefits to one or both sexes as inter- or intraspecific signals. Both sexes of the turquoise-browed motmot (
Eumomota superciliosa) are elaborately plumed with long racket-tipped tail. I investigated whether the racketed tail functions as a sexually selected
signal in one or both sexes by testing the predictions that males and/or females with the largest tails have: (1) greater
pairing success, (2) greater reproductive performance (clutch-initiation date, clutch size, and hatching success), and (3)
greater reproductive success. Yearling males with longer denuded rachises (wires) on the central tail feathers had greater
pairing success. In addition, adult males with longer wires paired with females who laid larger clutches, had greater hatching
success independent of clutch size, and fledged more young. There was no relationship between female tail plumage and pairing
success, reproductive performance, or fledgling success. These results are consistent with the hypothesis that male tail plumage
functions as a mate choice or status signal, but that the tail of the female does not function in a sexually selected context.
I discuss alternative hypotheses for the evolutionary maintenance of the elaborate female tail plumage.
Keywords Sexual selection - Social selection - Elaborate monomorphism - Pairing success - Reproductive performance - Fledgling success - Reproductive success - Tail plumage
Communicated by R. Gibson