November 20, 2008

CAPE ROYDS, ROSS ISLAND, ANTARCTICA– Male Adélie Penguins were seen this year at Cape Royds on Oct 21. First a trickle then a flood, by mid November most of the nests had been built, the males had found a mate and the eggs were laid. Cape Royds has a short breeding season; there is no time to waste in this process. Many penguin breeding pairs will return to the same nest site year after year re-bonding with each other and raising their chicks together. But not all penguins find their mates from the previous year. Some did not survive the winter, some may have found a new colony to breed in, others may simply decide not to breed this year and stay out near the ice edge. In these cases new mates must be found.

To attract a mate, males build nests out of small rocks then stand nearby bowing to females as they pass by. Females may just walk by, or step into the nest for a while then move on, or they may stay accepting the male as a partner and his nest as hers. What causes the female to select the nest she wants? There is no way to know for sure, but one thing for sure, not all Adélie Penguin nests are alike. The rock structure, although not warm and soft like other bird nests, provides a barrier to keep the eggs and small chicks from rolling or falling out. It also keeps the eggs above melt water that will flow through some parts of the colony as the weather warms and snow patches turn to small rivulets. Perhaps the females sense the merit of each nest to provide this protection for her chicks, maybe it is random, or maybe there are other factors we do not know about. Either way there is great variation in the nests as you can see by the pictures below.

This year the penguins must walk 50 miles over the frozen sea ice to get to their breeding ground at Cape Royds.

Once they arrive at Cape Royds, the males find a place that suits them and start to build their nests.

This is a well built average nest, the male is waiting for a female to join him.

The female is inspecting the nest.

She enters the nest to see how it works for her.

She decides to stay, the bond is made and this pair will raise some chicks.

Some nest builders use big rocks.

Some prefer small rocks.

This Adélie Penguin built a large nest.

Some penguins build small ones.

Perhaps this female chose this nest because it is well protected by the rocks. Skuas will have trouble attacking here.

This nest is out in the open and very vulnerable. It will be difficult to fend off the Skuas from taking the eggs and chicks.

This nest is very tidy and organized.

This nest is not.

As long as the snow stays frozen this nest will be okay, but when the weather warms up these parents may find their rocks washing away.

This penguin may have trouble finding a mate to join him in this nest.

As you can see, not all Adélie Penguin nests are alike, and just like people they all have their own sense of décor.