Able to withstand the harshest climate on earth, the birds of Antarctica are like no others. From the wandering albatross that can soar for hours and has the largest wingspan of any living bird, to the flightless emperor penguin that may travel up to 120 kilometres to reach open water to forage, Southern Ocean birds have mastered the challenges of polar living.
Though the Antarctic may seem inhospitable to life, for birds it has a number of advantages. The greatest is the lack of predators on land. Though penguins may encounter predatory seals and whales in the water, there are few threats to adult penguins on land. Skuas, another type of bird, may attack and kill chicks of penguins and other birds, but they cannot challenge adults. Petrels may prey on adult penguins, however. Flying birds like albatrosses and petrels similarly face few threats in the Antarctic.
To rear their chicks, some seek ice-free areas and build nests of pebbles on the ground, while others prefer to nest on rocky cliffs and ledges, like the Antarctic petrel. Adélie penguins are famous for stealing rocks from each other’s nests. These pebbles have been stolen back and forth for hundreds of years. Emperor penguins forgo nests entirely, and keep their eggs on top of the males’ feet, where a special area of featherless skin called a brood patch warms them. Regardless of the type of nest, penguins, albatrosses and petrels are all devoted parents, incubating eggs and raising chicks for several months. Some albatrosses may fly for thousands of kilometers to obtain food for their offspring.
In addition to relative safety from predators, the abundance of food sources during the austral spring and summer makes Antarctica a perfect place to raise young. Krill, fish and squid are all important food sources for flying birds as well as penguins. As described above, some birds also eat other birds, and may consume carrion from dead seals and birds. Access to prey becomes particularly critical during the breeding season. If they have to travel too far to find food, the chick might starve.
During breeding, many Antarctic birds gather in large colonies, some of which are among the largest bird colonies in the world. The Antarctic may seem like a peaceful place, free from the noise of human activity, but a large penguin colony full of squawking birds fighting for the best nest location is anything but serene. Nevertheless, these tough survivors exist in a delicate balance with their environment, and small disturbances can have a great impact.
The main threat to Antarctic birds is climate change. Changes in the distribution and extent of sea ice may affect breeding or prey availability. Climate-related changes in weather may increase precipitation, which can harm chicks that haven’t developed their adult waterproof feathers yet. In addition, climate change, ocean acidification, and human activities in the Antarctic could cause changes to the food web and bird habitats. Some species may find it challenging to adapt
Whether soaring or swimming, the common thread among these birds is the important role they play in Antarctica’s intricate food web, both as predator and prey. Not only do they provide a glimpse into the great biodiversity of this region, they also provide invaluable insight into the effects of climate change and human activity on ocean health.