Ernie Janes / House sparrow (Passer domesticus) in building, Scottish borders, UK, July.

David Perpinan / Common rock sparrow (Petronia petronia) feeding chicks in nest, filmed using an infra-red camera, Cuenca, Castile-La Mancha, Spain, June.

David Perpinan / Common rock sparrow (Petronia petronia) chick exploring outside nest, Cuenca, Castile-La Mancha, Spain, June.

David Perpinan / Adult Common rock sparrow (Petronia petronia) feeding chicks, Cuenca, Castile-La Mancha, Spain, June.

David Perpinan / Female Rock sparrow (Petronia petronia) feeding chick inside nest, filmed with an infrared camera, Spain, June.

David Perpinan / Rock sparrow (Petronia petronia) feeding chick outside nest, Spain, June.

Nick Saunders/ BIA / Le Conte's Sparrow (Ammodramus leconteii), Saskatchewan, Canada

Alan Murphy/ BIA / Grasshopper Sparrow (Ammodramus savannarum) male calling, Arizona

Greg Oakley/ BIA / Diamond Firetail (Stagonopleura guttata), Victoria, Australia

Greg Oakley / Diamond Firetail (Stagonopleura guttata), Victoria, Australia

Graeme Guy / Baya Weaver (Ploceus philippinus) male weaving nest, Singapore

Hougaard Malan / Quiver tree with sociable weaver (Philetairus socius) nest in morning light. Quiver Tree Forest, Keetmanshoop, Namibia. March 2011.