These are Macaroni penguins, which breed and nest from Chile to Argentina and the Falkland Islands to the Antarctic Peninsula (more info). Even though this often hilarious-looking penguin is the most numerous of all the world's penguins, it is less known than the handsome Emperor penguin of 'March of the Penguins' fame. (Find the baby Emperor penguin in this one!)
Others: Gentoos, Gentoo chick, Gentoo parent with chicks; leuchistic chin-strap, chinstrap parent and chicks; an Adelie that only a mother could love!.
The 'Cool Antarctica' website has other great shots : this is a pair of Macaroni penguins with a Chinstrap behind and to the right.