Black grouse males in Kuusamo, Finland

© Markus Varesvuo/Minden Picture

Ruffling feathers. Black grouses lekking

These showy males are squaring up in Kuusamo, Finland, a popular hang-out spot for black grouse as they take part in a flamboyant courtship ritual. They fan their tail feathers and inflate their necks while letting out a murmuring coo, hoping that a female selects them. This communal display is called lekking, and though we only see two birds here, these groups can number up to 200. Black grouse aren't the only animals known to participate in leks—bats, paper wasps, Atlantic cod, and fiddler crabs are among the many other species which go to the same lengths to find the right mate.