Breeding biology of the Andean cock-of-the-rock (<i>Rupicola peruvianus</i>)

The Andean cock-of-the-rock (<i>Rupicola peruvianus</i>) belongs to the Neotropical family Cotingidae, inhabiting the Andean mountains from Venezuela to Bolivia. Despite being a recognised and iconic species, most breeding studies of this bird have focused on its display behaviour at communal ‘leks’ rather than its basic nesting biology. Here, we present novel data on incubation behaviour and detailed descriptions of nests, eggs, and nestling development, with the first photographic evidence of nestlings being fed with vertebrates. We found 38 cup-shaped nests located along rocky walls near rivers or creeks in Peru, Ecuador, and Colombia. Nests were placed on rocky indentations along rivers, creeks, and waterfalls. The mean clutch size was two eggs. Eggs were beige with brown/green spots mainly located towards the wider end. Eggs measured 46.7 ± 1.2 mm by 32.7 ± 0.3 mm and weighed 25.6 ± 0.9 g. The incubation and nestling period lasted 26.0 ± 1.3 and 40.0 ± 2 days, respectively. During the incubation period, the female was the only parent attending the nest, with an average daily nest attentiveness of 87.3 ± 6.6%. The nestlings grew at a logistic curve rate (K) of 0.135 ± 0.005 g and kept their body temperature constant at 39.3°C only after day 30 of development. Detailed natural history accounts of the nest locations are necessary to generate long-term monitoring and successful conservation strategies of Neotropical species, especially for large frugivorous birds such as <i>R. peruvianus</i> that have long nesting cycles, specific nesting locations and are highly sensitive to forest fragmentation.