Rick is right. The skuas take the ecological place of rats down here. They are basically a polar seagull. In years past when McM had a dump the Skua population began to grow. To this day you have to be careful walking around with food. Some of them have learned to fly in your face. If they can startle you enough to drop the food then they have a free meal.
The funniest (unconfirmed) skua story I know of is ‘The day it rained chickens in McMurdo’
It seems a crate of frozen chickens thawed and spoiled and were hauled to the dump. The skuas tried to fly off with them but they were too heavy and as they flew over town many of the chickens fell from their grasp onto the streets and buildings.
These days we are more conscious about garbage. Nothing gets dumped anymore. All the food waste gets returned to the United States for disposal. As a result the skuas do not return in the numbers that they used to.