Kim Taylor / Tree bumblebee (Bombus hypnorum) workers patrolling entrance to nest in bird box. Surrey, England, UK, May. Long exposure.

Pal Hermansen / Artwork 'Unsatiable' by artist Astri Tonoian. Valer, Ostfold County, Norway. July 2014.

Pal Hermansen / Artist Astri Tonooian and daughter, present 'Unsatiable' to the public. Valer, Ostfold County, Norway. September 2014.

Terry Whittaker / Red squirrel (Sciurus vulgaris) feeding on top of bird box, Black Isle, Scotland, UK. March

Markus Varesvuo / Redstart {Phoenicurus phoenicurus} male singing on top of birdhouse, Estonia.

Peter Cairns / 2020VISION / Group of children and adults building bird boxes at a Fell Care Day, Cumbria, England, UK, October 2011.

David Tipling / Purple Martin (Progne subis) boxes in garden, in Cape May, New Jersey, USA, May.

David Tipling / Eastern Bluebird (Sialia sialis) flying to nest box, Cape May, New Jersey, USA, May.

Konrad Wothe / Blue Tit (Cyanistes caeruleus) looking out of nestbox, Germany

Konrad Wothe / Blue Tit (Cyanistes caeruleus) with nesting material, Germany

Mark Raycroft / West Highland White Terrier (Canis familiaris) sitting in garden by birdhouse

Bengt Lundberg / Male Sparrowhawk perched on birdhouse, Sweden