Antarctica

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Antarctic birds

Unusually for Antarctic birds, snow petrels seem to apply some thought to the practicalities of a nest site. This pair are at the intrance to their nest which has been made in a natural crevice amongst some large broken-up rocks. This is a frequent choice for a nest site though not always available or in plentiful supply as snow petrels nest very far south and such crevices are frequently snowed or iced up.

Attempting to approach a nest (as I did on many occasions when helping in a long term programme on nesting success) brings out the worst in snow petrels. A well aimed stream of foul smelling, bright pink, oily, semi-digested krill mixed with oily stomach secretions would come in your direction in their (admirably unpleasant) defence mechanism.

Snow petrels have been known to nest far inland on the Antarctic continent, nearly 200km. from the nearest sea that they must travel to in order to feed. They must nest on rock and in these cases choose nunataks isolated outcrops of tall rock ridges and mountains that protrude above the surrounding ice from the bed rock.

There are more Adelie penguins than any other penguin species. They live in the deep south and as such frequently have to cross many kilometers of ice still bound to the continent or islands to reach land in the spring where they can build their nests. Sometimes they have to travel as much as 100 kilometers, though usually 20-40 is more usual. A long walk nevertheless.

This pair were early arrivals in spring at an Antarctic Island near the northern edge of their breeding range and only had about half a kilometer to waddle and "toboggan".

Tobogganing is a way of getting around where there is smooth snow or ice. The penguin lies on its stomach and propels itself along using its feet, an efficient use of energy and one where the penguin can easily keep up with a running man.Adelie penguins weigh about 5kg and are around 70cm tall. They winter on the pack ice where the air temperature is higher than on land and where they can find cracks in the ice to fish through. In October, they begin to move south to their breeding grounds, the males arriving first to establish territories and nest spaces with the females arriving shortly afterwards.

some hours later have returned. In the meantime the tide has gone out. Still attached to the land is the "ice-foot" an ice step left behind as the tide rises and falls in the winter months to which the floating sea ice is loosely attached. When the sea ice breaks out, the ice-foot is left behind for a period of days to weeks before rising temperatures and the waves cause this to break off too.

So what was a short hop down for the penguins is now a step too high for them. I spent a couple of hours one afternoon watching and following an ever increasing number of penguins as they came back from their fishing trip. They wandered up and down the shore-line trying to find somewhere to get up, but to no avail. Eventually, the tide came back in and so they floated back up to the right level and were able to get back to their nests. The ice-foot broke off completely a few days later in a mild storm.