Please turn on JavaScript. Media requires JavaScript to play.

In a bizarre reaction to changing food supplies, great white pelicans have turned to eating live gannet chicks.

This adaptive behaviour, first revealed by biologist Marta de Ponte Machado, has now been captured on film by a BBC natural history camera crew.

On the island of Malgas in South Africa, the pelicans attack any gannet chick that is left undefended by its parents and is small enough to swallow.

As a result, entire gannet colonies are in danger of being destroyed.

"Pelicans gobbling gannets" is broadcast within the Birds episode of the BBC series Life at 2100GMT on BBC One on Monday 9 November.