Researchers saw an adult Abert’s towhee throw two nestlings out of its nest after the researchers had collared the nestlings’ throats as a part of a study of the nestlings’ diet. The researchers also observed yellow- chats retrieving food from their nestlings after throat ligatures were applied. The researchers had no problem getting food samples from song sparrow nestlings with throat ligatures.

The researchers suggest that when nestlings are small compared to their parents, the parents are more likely to heave them out of the nest when they detect a foreign object, like a throat ligature, associated with the nestling.

The paper was published in The Wilson Journal of Ornithology.

The full paper is available here.