Twelve endangered rockhopper penguin chicks hatched at a zoo in Austria.

The newborn penguins were born in April and spent their first few weeks under the care of their parents at the Schonbrunn Zoo in Vienna.

Zookeepers eventually took charge of the adorable chicks, which received round-the-clock care from their handlers.

The young birds were fed thrice a day. They were placed in the zoo's Polarium section to learn to dive and catch fish.

Zoo Director Dr. Stephan Hering-Hagenbeck said: 'These animals face major threats from climate change, overfishing, and ocean pollution.'

He added that the successful hatchings marked a milestone for the zoo, which has co-ordinated the European Endangered Species Program for both Northern and Southern Rockhopper Penguins.

Zoological assistant Sabine Fruhwirth said: 'We have the most successful breeding program in Europe.'

More than 100 penguins bred at the Schonbrunn Zoo now live in other European zoos.

Northern rockhopper penguins are listed as 'endangered' on the IUCN Red List of Threatened Species. The main threats to their survival are climate change, overfishing, and oil spills.