Parental Roles and Prey Choice in the Endangered Black-and-chestnut Eagle

The Black-and-chestnut Eagle is listed as Endangered globally and Critically Endangered in Ecuador, where it faces severe threats from habitat loss and human persecution. However, many aspects of the species’ ecology remain poorly understood, making it difficult to formulate effective conservation recommendations. In particular, little is known about how diet differs between sexes, despite this eagle exhibiting strong sexual size dimorphism, with females being significantly larger than males.

A new publication, led by Juan Sebastián Restrepo-Cardona, a scholar supported by our Neotropical Student Education Program, analyzed prey deliveries to nests in the Andean region of Ecuador to evaluate differences in prey size and composition between males and females. Results showed that males contributed more than twice as much prey to nestlings as females. Both males and females targeted the same primary bird and mammal prey species, but when it came to less common prey, notable distinctions emerged: females more commonly took larger mammals such as primates, while males more frequently captured rodents and ground birds.

This latter finding is particularly noteworthy, as it indicates that male Black-and-chestnut Eagles more frequently target chickens and other domestic birds. As a result, males are more vulnerable than females to human persecution—a major concern in Ecuador, where these eagles are often killed in retaliation for poultry predation. The findings highlight the value of long-term nest monitoring as a tool to guide effective conservation strategies.