Markus Varesvuo / Linnet (Carduelis cannabina) adult male, Uto, Finland, August

Markus Varesvuo / Fox Sparrow (Passerella iliaca) Uto, Finland, December

Loic Poidevin / Greater Flamingo (Phoenicopterus roseus) juvenile with ruffled feathers, Camargue, France, May

Mary McDonald / Turqouise-fronted parrot (Amazona aestiva) puffed up, Pouso Alegre, Pantanal, Mato Grosso, Brazil. August.

Ben Cranke / Siberian Tit (Poecile cinctus) perched on twig, Finland. February.

Markus Varesvuo / Collared Dove (Streptopelia decaocto) Liminka Finland, January

Markus Varesvuo / Black Redstart {Phoenicurus ochruros} female on ground with ruffled feathers, Hungary.

Christophe Courteau / Burrowing Owl (Athene cunicularia) portrait with feathers fluffed up, Hato El Cedral. Llanos. Venezuela.

Ramon Navarro / Little owl (Athene noctua) ruffling feathers, Seville, Spain, July.

Mike Wilkes / Redwing (Turdus iliacus) puffed up against the cold, Warwickshire, England, UK, December.

Mike Wilkes / Blackbird (Turdus merula) female puffed up against the cold in the snow, Warwickshire, England, UK, December.

Roger Powell / Great spotted cuckoo (Clamator glandarius) perched on a post, with ruffled feathers, Castro Verde, Alentejo, Portugal.