First Documented Case of Pseudo-egg Incubation by Coragyps atratus in a Semiarid Environments

Inanimate objects, known as pseudo-eggs, have been observed in the nests of various bird species, often being incubated as if they were real eggs. This study presents the first documented case of pseudo-egg incubation by Coragyps atratus , observed in the semi-arid region of Paraíba, Brazil, where an individual treated a mollusk shell as an egg, displaying nesting behavior and aggression toward potential predators. The vulture's presence at the site for over a month coincided with the species' average incubation period, suggesting a significant behavioral interaction with the object. This report expands knowledge on bird-pseudo-egg interactions and underscores the need for further studies to understand the underlying factors driving such behaviors.