Unpleasant meals may help manage crow predation on bird nests

Crows are notorious for robbing eggs and chicks from other birds nests, especially where crow numbers have been boosted by human activity. However, research led by UCT student Angela Ferguson, indicates one way to stop the marauding crows. On the Berg River estuary, Angela was able to teach wild pied crows not to eat eggs, by setting up artificial nests with vomit-inducing eggs in them. This technique, called Conditioned Food Aversion, exploits the crows own smarts by allowing them to learn that eggs are a nasty meal and best avoided. By matching artificial nests to those of endangered shorebirds living at the estuary, such as chestnut-banded plover, the team hope to help more chicks survive and bolster the shorebird populations. Historically, Pied crow were not abundant at the Berg River, and have only moved in because humans have modified the environment by providing crow nest sites. Angela and her team consider this justification for the non-lethal intervention and points out that it is perhaps preferable to alternative methods of predator control, including culling.

The research is published in the Journal for Nature Conservation