MARCH OF THE PENGUINS

Updated on: Friday, February 05, 2010

The emperor is the giant of the penguin world and one of the largest of all birds. It is the only penguin species to breed through the cold, dark winter, with temperatures as low as -50°C and winds of up to 200 km per-hour. If, so far, there has been a paucity of information on the number and distribution of emperor penguin colonies, it could be attributed to their habit of breeding on sea-ice during the Antarctic winter. Access by researchers is difficult during these winter months. And by the time people have access to the colony locations during the summer, the penguins have already left their breeding grounds for the open ocean.

But a discovery by mapping expert, Peter Fretwell, at British Antarctic Survey (BAS), UK, reveals that satellite images of Antarctica can be used to locate emperor penguin breeding colonies. Explains Fretwell, “This can be done by identifying guano (excrement of sea birds) stains on the ice. We can’t see actual penguins on the satellite images because the resolution isn’t good enough. But during the breeding season the birds stay at a colony for eight months. The ice gets dirty and it’s the guano stains that we can see from space.”

As part of the study, BAS scientists used satellite images to survey the sea-ice around 90% of Antarctica’s coast. The survey identified a total of 38 emperor penguin colonies. Ten of those were new. Of the previously known colonies, six had re-located and six were not found. This research builds on the work by French scientists who extensively studied one colony and found that the population was at a significant risk due to climate change. The six colonies — not found in this study — were at similar latitude suggesting that emperor penguins at lower latitudes may be at risk all around Antarctica.

Fretwell adds, “To confirm that what we were seeing were penguins, we recently sent an airborne recognisance mission to fly over one of the newly-found colonies at Clarke Bay at the base of the Antarctic Peninsula. The photos from this survey have confirmed that the reddish brown stains really are penguin colonies.”

For this project, Fretwell worked with penguin ecologist Phil Trathan. They are now proposing further studies by BAS to carry out additional aerial surveys and to assess the global population of this `charismatic’ species.

Recent computer modelling studies (based on over 40 years of population data in Terre Adélie in the Antarctic) have predicted that populations have a high probability of declining by 95% or more in the face of climate change. These predictions are based on one colony, located relatively far north at 66.6° south. The new methods developed by Fretwell and Trathan make it possible to test these predictions at other locations where emperor penguins breed, particularly further south where the majority of emperor penguin colonies occur.

This method of identifying emperor penguin breeding colonies has helped British scientists provide a baseline for monitoring their response to environmental change. Now they know exactly where the penguins are. “The next step will be to count each colony so that we can get a much better picture of population size,” adds Fretwell.

Times of india

MARCH OF THE PENGUINS

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