As the radio-station Cupcakes poured down into the freezing temperatures of Antarctica, they froze into cupcake-sized hail and diminished the penguin population, one by one, until...
The Titanic plunged into Antarctic and wiped out the remaining penguins and made a huge gash in the country that could be seen from space, where the aliens thought the shape looked funny
So, like any sensible Americans Aliens would do, they decided to invade.