This is an Adelie penguin, the type I saw swimming by our ship.
I was never able to photograph them swimming, but believe me, it was a beautiful sight. The most amazing part was watching them land. They shot straight out of the water and landed on their feet!
My friend J.D. took this photo of a nesting Adelie during our visit to Palmer Station, the United States Antarctic marine science base. Two of the Palmer scientists took us to a nearby penguin nesting area (called a rookery). I will never forget it--penguins as far as I could see! Because it was the beginning of their breeding season, they were building or guarding nests.
Most of the penguins at the rookery were Adelies. They were tiny--the adults were a little over two feet tall. They didn't seem afraid of me. In fact they were quite curious! They walked right by me, inspecting me with their beady black eyes.
Adelie penguins build nests of pebbles. The penguin picks up a pebble, waddles over to the nest, puts it down, then goes back for another pebble. Sometimes the penguins steal pebbles from each other's nests! After the Adelie parents have built a nest, the female lays her eggs. Then she goes out to sea to feed (krill is the main food). This usually takes several weeks. While she's gone, the male guards the nest. He doesn't leave, not even to eat. Penguin parents, like human parents, are very faithful.--Vicki Johns
Source: Moss, Sanford A. Natural History of the Antarctic Peninsula. New York: Columbia University Press, 1988.
Photo by J.D. Goodlaxson, Martin Marietta Energy Systems