The Spotted Barbtail (Premnoplex brunnescens): male and female parental effort during the nestling period

We document male and female roles in nestling care of Spotted Barbtails (Premnoplex brunnescens) including feeding rates and temporal patterns of provisioning by each sex. Using 128.5 hrs of video from color marked and molecularly sexed individuals at two nests, we confirm that both sexes of Spotted Barbtail provision nestlings. Spotted Barbtail females in our study invested more heavily in nestling care than males, making 73% of feeding visits. Females also visited the nests nearly twice as often as males, averaging 1.24 visits/nestling/hr compared to 0.69 visits/nestling/hr for males. While Spotted Barbtails exhibit many of the features assumed to favor social and genetic monogamy, intriguing aspects of nest building and incubation leave open the possibility that this species is unusual among the Furnariidae and utilizes extra-pair matings as a part of the reproductive strategy.