Breeding biology and biometrics of Silver-beaked Tanager Ramphocelus carbo connectens in south-west Brazilian Amazonia

Abstract

We present new data on the breeding biology and biometrics of Silver-beaked Tanager Ramphocelus carbo in south-west Brazilian Amazonia. R. carbo is widely distributed in South America, but its reproductive ecology is little studied. We made observations on the species in a terra firme forest fragment in the capital city of the state of Acre, between 1999 and 2020. We monitored 12 nests between 2012 and 2020, built at a mean height of 1.3 m above ground. Clutch size was two eggs, incubated for 13 days. We monitored the development of 11 nestlings: minimum hatch weight was 1 g and young fledged with a mean mass of c.18.9 g. The constant growth rate (K) of nestlings was 0.48 with a growth asymptote of 22.1 g. Daily survival rate was 91% and 98% during the incubation and nestling periods, respectively. Mayfield success in the incubation and nestling periods was 28% and 74%, respectively. Apparent nesting success in the incubation and nestling periods was 62% and 82%, respectively. We recorded a minimum longevity of 11 years, six months and 28 days. The subspecies R. c. connectens breeds mainly in the rainy season (October–January) overlapping with the moult period.