Distribution and abundance

During this study we have refined techniques of aerial reconnaissance and photography for use as a bird census technique in the Antarctic.

Aerial reconnaissance

Using a C130 Hercules, the Victoria Land coastline has been searched from the air, to locate the Adélie colonies in the Ross Sea Region.

Aerial photogaphy

Adélie penguin colonies are photographed from a helicopter or C130 Hercules, using high-speed, fine-grain, black and white film. This is carried out in late November or early December to coincide with the incubation phase of breeding. At this stage in the cycle, one bird is incubating while its mate is at sea feeding. As there are few non-incubating birds ashore, an accurate count of breeding birds can be obtained.  From these aerial photographs we are able to count the number of breeding pairs in each colony and establish baseline data on population trends.

Aerial Photograph of Cape Bird Adélie colony, Ross Island
Aerial photograph of Cape Bird Adélie colony, Ross Island

Counting

The films are developed and printed.  Prints are enlarged and breeding birds are marked with a black dot. This ensures each breeding bird is included only once when counting the dots! In this way we get a reasonably accurate measure of the number of breeding pairs. Land-based counting is difficult, and although the breeding penguins are sitting on eggs and do not move much, they all look exactly the same. It's very easy to get 'lost' and lose count. Large colonies (up to 250 000 breeding pairs) are too big to attempt to count even from the land.

Print ready to be marked and enlarged for counting Photo ready for counting
Print ready to be marked and enlarged for counting Photo ready for counting

At the colonies we assess:


Adélie Penguins