David Pattyn / Black necked grebe (Podiceps nigricollis) adult bird spreading its wings and waiting for the submerged partner to appear in front and perform the courtship dance. This is early in the breeding season,...

David Pattyn / Great crested grebe (Podiceps cristatus) fluffing up its feathers, during courtship dance, whilst its mate dives underwater, The Netherlands. April.

David Pattyn / Black necked grebe (Podiceps nigricollis) adult bird spreading its wings in anticipation of the partner during courtship. The Netherlands.April 2014

Markus Varesvuo / Black Grouse (Tetrao tetrix) ruffling feathers, Askola, Finland, March

Roger Powell / Little owl (Athene noctua) perched on a fence post, ruffling its feathers, Castro Verde, Alentejo, Portugal, April.

John Chan / Juvenile White-tailed kite (Elanus leucurus) ruffling its feathers, Southern California, USA.

Sandesh Kadur / Slow motion clip of an Amur falcons (Falco amurensis) shaking and ruffling feathers, part of a large flock congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland,...

Sandesh Kadur / Amur falcon (Falco amurensis) stretching wings and ruffling feathers in the rain, part of a large group congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, Ind...

Sandesh Kadur / Amur falcon (Falco amurensis) shaking its feathers, part of a large group congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.

Marie Read / Short-eared Owl (Asio flammeus) shaking after preening while perched on fencepost, Boxelder County, Utah, USA, May.

John Chan / Male Anna's hummingbird (Calypte anna) stretching, ruffling feathers and taking flight, Southern California, USA, January.

Philippe Clement / Grey heron (Ardea cinerea) perched in tree ruffling feathers, Belgium, March.