Gentoo penguins, Antarctica

Gentoo penguins differ in appearance from the standard tuxedo-wearing penguins many of us imagine. Instead, they are characterised by bright-orange bills and white stripes above the eyes that extend across the tops of their heads. Their breeding and nesting habits have earned them a reputation as one of the most romantic seabirds. To signal interest in becoming a pair, gentoo penguins build intricate nests together and share pebbles as a sign of romantic interest. The nests are then used for laying eggs.
© Nature Picture Library/Alamy