The normal route to feeding areas is blocked after two giant icebergs broke off the Antarctic ice sheet and are now floating between the Ross Island and the open ocean.

Almost 150,000 breeding pairs of emperor and Adelie penguins are finding it increasingly difficult to feed their chicks.

Two huge ice blocks - one the size of Jamaica - broke off the vast Ross Ice Shelf, south of New Zealand, in March 2000.

They have now floated between Ross Island - where the penguins breed - and Franklin Island, blocking short routes to the open sea.

Energy used up

Penguins come ashore to breed, then take it in turns to go hunting for food like fish, crustaceans and squid.

They walk at a pace of less than two kilometres an hour and they are now having to travel up to 50 kilometres further than usual.