Golden Eagle cainism

Two chicks will hatch from their eggs just a few days apart in their rock wall nest. Only one will have a chance of surviving: the weaker one will be eliminated by the stronger one! In biology, this behaviour is called "cainism".
It is a common phenomenon among daytime birds of prey, part of a species survival strategy that selects the strongest offspring from birth to increase their chances of reaching maturity. It's a huge undertaking for the parents to feed a ravenous hatchling, which can grow from 100g at birth to 5kg by the time it flies!