Wasp Filmed Attacking Baby Bird and Eating Its Head

An aggressive species of wasp has been filmed attacking a baby bird in its nest and eating its head. The attack lasted over half an hour, with scientists reviewing the footage seeing the bird bitten on the head repeatedly before succumbing to its injuries.

Agelaia pallipes, a species of social paper wasp found across South America, is known to feed on the decaying flesh of dead animals. However, there are few recorded cases of these wasps preying on vertebrates.

In a study published in the journal Ethology, researchers led by Sjoerd Frankhuizen, from Wageningen University & Research, the Netherlands, documented the encounter. The team was assessing the reproductive behaviors of the lined seedeater, a species of songbird, in south-east Brazil. They placed cameras near nests and recorded them for two hours per day when nestlings were between one and six days old.

When they retrieved the footage, they discovered the attack. You can view the video here.

Originally, the nest contained three baby birds. Two had died of unknown causes, with wounds indicating one of them had been scavenged by ants and other insects. The third was filmed alive in the nest.

Footage showed a wasp flying into the nest and landing on the head of the nestling. The nestling initially moved, prompting the wasp to fly away. However, it returned shortly after and was seen biting the bird's head. Blood could be seen coming from the nestling's head, suggesting an injury had been inflicted. On its next return, the wasp tore a piece of skin from the bird's head. Shortly after the bird stopped moving, which the researchers believe was the point it died.

dead nestling
Images showing the nestling after being attacked and killed by the wasp. Ethology 2020/Frankhuizen et al

The researchers believe the wasp may have been attracted to the nest by the scent of the nestling's dead siblings.

Among the other nests they had recorded, they found other dead nestlings with similar wounds to the bird attacked by the wasp. However, their cameras did not record their deaths so determining wasps were also responsible was not possible.

They said that while these wasps are known to feed on dead vertebrates like nestlings, the latest discovery adds to the handful of reports showing they will actively prey on live birds. "This, and the fact that we found additional nestlings with similar wounds five days after the recorded predation, indicates that wasps might be overlooked as nestling predators," they wrote.

"Nest predation is a major selective pressure in birds, and insects are rarely assumed to play a notable role in this process. Further research is needed to better understand the nature of the relationship between wasps and birds."