Finding emperor penguin colonies
Emperor penguins are big birds and they usually form large colonies. So how difficult can it be to find out where they gather to breed?
In short, very! This is partly because they decided a long time ago to live in one of Earth’s most inhospitable environments. Also, the penguins breed throughout the Antarctic winter and most of the colonies we know are situated on fast ice (frozen sea attached to the Antarctic continent). Moreover, emperor penguin colonies are often surrounded by massive icebergs! One could be within a few hundred metres of them and never see them.
Why is it difficult to track penguins?
Unlike other birds, emperor penguins neither have fixed nests nor are they territorial. The males take over the egg from their mates, put it on top of their feet and cover with a skin fold of their bellies.
Throughout the winter and while they incubate their eggs they move around quite a lot! An emperor penguin colony is very dynamic; during the winter storms the penguins huddle. But when the worst weather is over the colony spreads out, shifts location, the huddles reform during the next blizzard.
Over a few months, the penguins – depending on the size of the colony – can cover an area of several square kilometres with guano! Thankfully today’s satellites have a high enough resolution to pick up these patches.
Technology assisting discovery
Researchers from the UK, USA and Australia used satellite images to estimate the size of the global population of emperor penguins (Fretwell et al. 2012).This is the first time that such work has been attempted. Many of the now known 46 colonies have either never been visited by people or have not been visited for a very long time. So using images from space makes these colonies more “accessible”. A few seasons prior to this work, scientists visited some emperor penguin colonies and conducted ground counts of the penguins. In a process call “ground truthing”, these numbers were used to calibrate the satellite images. That means that the numbers from the ground counts, which are quite accurate, were compared to counts made of the satellite images and compared. Overall, this process worked quite well and we now think that are about 595,000 adult emperor penguins in Antarctica.
People and penguins
For people, many colonies are very difficult to reach. But we in the Australian sector of Antarctica are lucky since two emperor penguin colonies are relatively close to one of our Antarctic bases, Mawson Station.
The colony at Auster has about 12,000 breeding pairs while there are about 3000 breeding pairs at Taylor Glacier.
Taylor Glacier is the only colony known to occur entirely on land. A second one, at the Dion Islands, at the Antarctic Peninsula has probably ceased to exist. At a number of other colonies where small islands are near their breeding area, emperor penguins often climb ashore in early summer.
Taylor Glacier is an Antarctic Specially Protected Area (ASPA) and special permits are required to enter the area.