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Ice Shelf Ruptures Threaten Thousands of Penguin Chicks

Giant Icebergs Endanger Penguin Chicks

Reuters News Service, Jan. 14, 2002

Tens of thousands of baby penguins face starvation after two giant icebergs broke off the Antarctic ice sheet and blocked their parents' access to feeding areas, a New Zealand government agency said Friday.

Adelie and emperor penguins nesting on the Ross Island rookeries are now forced to walk long distances over the icebergs to obtain food for their chicks, born during the November-December breeding season.

"The penguins are having to walk 50 km (31 miles) further than usual to reach the sea," said Dean Peterson of Antarctica New Zealand. The flightless birds travel on land at just one to two km per hour.

The problem could halve the chick survival rate at the three Adelie penguin colonies on Ross Island, estimated at 130,000 breeding pairs, said Peterson. In all Antarctica, there is an estimated three million Adelie penguin breeding pairs.

Around 12,000 breeding pairs of emperor penguins, the largest penguin species at up to four feet tall, are also affected.

The icebergs broke from the vast Ross Ice shelf, south of New Zealand, in March 2000 and are now sandwiched between Ross Island and Franklin Island, 93 miles to the north.

Peterson, a U.S. scientist working for the NZ agency, estimated that penguins were taking days to make the round trip to the sea to fish, and then back to their nests to regurgitate food for their chicks. "At that point they are quite exhausted and probably don't have much to regurgitate," he told Reuters.

Penguins already have long odds on reaching adulthood, with only 10 percent surviving beyond adolescence.

"We are probably looking at halving that again; we are sitting down at maybe the five percent rate," Peterson said, adding some penguins already appeared to be abandoning the Ross Island rookeries to breed elsewhere.

Penguins come ashore to breed and then take it in turns to leave the nest to fetch crustaceans, fish and squid to feed their young. Researchers say large chunks of the Antarctic ice sheet are breaking off for several reasons, including global warming.

Emperor and Adelie penguins are restricted to Antarctica. The emperors weigh up to 66 pounds while Adelie penguins are much smaller, weighing around 11 pounds.