Predation on a Roughskin Anole (Anolis trachyderma) by a Smooth-billed Ani (Aves: Cuculidae)

Abstract

This species has a disjunct distribution east of the Andes in the western Amazon of Ecuador, Colombia, Peru, and Brazil. In the Ecuadorian Amazon, it is present between 150 and 1,400 m asl in well preserved evergreen forests, most frequently in primary forest and less commonly along the borders of rivers and forest clearings (Ayala-Varela 2004). During daily activity, it forages in leaf litter, around logs, and in small shrubs (Ayala-Varela 2004).Smooth-billed Anis (Crotophaga ani) have an extensive distribution from Florida (USA) to northern Argentina, where they occupy a wide variety of habitats (BirdLife International 2023). They are generally diurnal and considered generalist predators that feed on arthropods and small vertebrates, including lizards. They typically forage near cattle in grasslands, disturbed open habitats, and forest borders, and they frequently perch in low vegetation, such as shrubs and small trees, between feeding events (Bent 1940;Ridgely and Greenfield 2001;Cooke et al. 2019).At 1455 h on 9 July 2021, while traveling to the Cuyabeno Wildlife Reserve in the Ecuadorian Amazon, we stopped near Manuel Galindo between the Coca River and Cayambe-Coca National Park in Napo, Ecuador (-0.138053, -77.619137), where we observed Smooth-billed Anis feeding on insects and witnessed one individual on the upper branch of a small tree next to the highway with a captured adult A. trachyderma in its beak (Fig. 1).Although records of predation on other lizard species by C. ani exist, to our knowledge this is the first report of predation on A. trachyderma. This is likely an unusual event given the habitat preferences of the two species. Anolis trachyderma is a tropical forest specialist (Castañeda et al. 2020), whereas