Resumen

The Black Antbird (Cercomacroides serva) inhabits the east Andean foothills and Amazonian lowlands from Colombia to north Bolivia and western Brazil. It is uncommon throughout its distribution. We provide the first nest and egg description for C. serva with detailed information on bi-parental incubation and nestling feeding behavior. We found four nests at two elevations in the buffer zone of Manu National Park in southeastern Peru. The C. serva nest is a pensile hanging cup, much higher at the back that at the front, made with dark fibers, dry leaves, sticks and fresh moss. The entrance was strongly oblique in three of the four nests. Egg coloration varied between and within the two eggs clutch size. On average, parents made 5.7 6 2.08 (6SD) foraging trips per day that lasted 39.2 6 36.17 mins, resulting in 84.6 6 9.2% nest attentiveness. Both sexes share daytime incubation, but night incubation was exclusively conducted by the female. Nest attentiveness did not differ between males and females, but daytime incubation bouts did vary between the sexes. Afternoon incubation was mainly conducted by the female (77.7%); in contrast, morning incubation was conducted primarily by the male (66.1%). The nestling period was 12–14 days, and the female spent more time feeding and brooding the nestling, a behavior that differs from that of other antbirds. Overall, nesting characteristics of C. serva resemble previous reproductive information published for other Cercomacroides species.