Playful birds: cormorants and herons play with objects and practice their skills

Resumen

Play is a behaviour known mostly for mammals, although birds are recorded to play as well. Here I describe the play behaviour for two bird species, the Neotropic Cormorant (Phalacrocorax brasilianus) and the Green Heron (Butorides striata) in southeastern Brazil. Juvenile and adult cormorants were recorded to manipulate sticks, leaves, rootlets, and plant debris while on the ground. They also played with sticks, leaves, pods, and plant debris, as well as live or dead fish while in the water, repeatedly grabbing the object and submerging it. When the object was a fish, they tossed it in the air as well. Juvenile herons played with small pieces of wood, fruits, and other floating objects, which they picked up and tossed repeatedly in the water. The behaviours recorded for the cormorants and herons qualify as object play, i.e., frolicsome interactions with an inanimate object including exploratory manipulation. This behaviour is regarded as having an important role in general motor development and for practice of particular skills, mostly foraging and breeding.