The Magellanic penguin (Spheniscus magellanicus) has a characteristic white stripe on its black head that starts at the eye, goes around the ears, the chin and joins at the throat. The back of the penguin is black, and the belly is white, with two black stripes between the head and the torso, the lower strip being in the shape of an inverted horseshoe. Medium sized, with a height of about 70 cm and a weight of between 3 and 4 kilos, it is the most emblematic species of penguin of the Spheniscidae family living in Argentine territory. During the southern winter it reaches the north of Chile and the south of Brazil, while in summer it is a very common species in waters near Tierra del Fuego.
The Magellanic penguin feeds on fish, feeding on species such as silversides, anchovies, squid, krill and other crustaceans. It fishes both during the day and at night, although there are many specimens that return to land when it gets dark. To catch its prey it uses a hunting strategy also seen in other marine predators: swimming in concentric circles that narrow around the shoals of fish until they are thrown towards the centre of the shoal to eat.
As far as reproduction is concerned, the eggs are laid in October, although they reach their nesting area during the previous month to prepare the nests. It is a species that is highly faithful to its breeding sites, swimming up to hundreds of kilometres to nest in the colony where it was born and usually using the same burrow year after year. This burrow is usually made underground or in caves or cracks in the ground, and several pairs can be found in the same cave.
Gestation lasts 42 days, during which time the male and female take turns to hatch the eggs and feed at sea. At birth, the chicks have a dirty, uniform grey down, although by February of the following year they are already self-sufficient. In April, the migration to the South Seas begins. During the breeding season, the main cause of mortality of the chicks is predation by foxes, skunks and armadillos. In addition, heavy storms can also knock down their nests or they may not protect the chicks properly from the sun. The shells of the eggs are very thick, so few of them break under the weight of the parents and the two eggs they lay each breeding season usually come through.