This is the shocking moment a mother stork tossed one of her chicks out of the nest to die to give the rest of her brood a better chance of survival.

Footage shows the mum staring at the four birdlings that were huddled together under her in Amur Oblast, Russia on May 16.

The scene recorded by a nature reserve camera quickly turned grim when she selected the smallest and weakest one that was only two days old.

She plucked it with her long beak, swung it repeatedly against twigs and branches.

The unhesitating parent then flung the chick over to the side of their shelter, perched on top of a tall tree.

Immediately, she went back to her three surviving chicks, picking out scraps of food for them to gulp down.

Experts say that white storks usually give birth to clutches of between two and five eggs.

But when food supplies are low, they will often sacrifice the weakest chick from the nest to give the others a better chance of survival.

The footage was shared from a livestream camera by keepers at Berezovsky Reserve.

Professor Anton Sasin, a local ornithologist from Far Eastern State Agrarian University said: 'One of the chicks has been thrown out by our stork.

'And as if nothing had happened, the parent continued to feed the remaining three storks.'

The parent storks, named Amur and Zeya by conservationists, had hatched their four chicks over several days starting May 9.

The youngest was born on May 14, but appeared weaker and less developed than its siblings.