Spotted eagle owl (Bubo africanus) at nest box, Paternoster, Western Cape, South Africa, Africa

Bird nest boxes in the Forest of Bowland, Lancashire, England, United Kingdom, Europe

A collection of colourful bird boxes in Hveragerdi, Iceland, Polar Regions

A collection of colourful bird boxes in Hveragerdi, Iceland, Polar Regions

Bluetit bringing food to its chicks in a nest box, England, United Kingdom, Europe

Hanami Bento

Baby hatch at the children's clinic Kemperhof, Koblenz, Rhineland-Palatinate, Germany, Europe

Boreal Owl or Tengmalm's Owl (Aegolius funereus), looking out of nest cave

Boreal Owl or Tengmalm's Owl (Aegolius funereus), looking out of nest cave

Little owl (Athene noctua), young bird looking out of the entrance of the nest box, Muensterland, North Rhine-Westphalia, Germany, Europe

Beehive, artificial nesting box for honey bees, Baden-Wuerttemberg, Germany, Europe

Four young common kestrels (Falco tinnunculus) in nest box, Hesse, Germany, Europe

Tawny owl (Strix aluco) flies at night with a yellow-necked mouse (Apodemus flavicollis) in its beak to the nesting box, North Rhine-Westphalia, Germany, Europe

Reptile incubator, eggs, illustration, zoo, Bristol, England, United Kingdom, Europe

Nest box for insects, insect hotel, courtyard, St. Martin Church, Weismain, Upper Franconia, Bavaria, Germany, Europe

Colourfully painted bird house at the Rosenheim 2010 State Garden Show, Rosenheim, Bavaria, Germany, Europe

Bird nesting box on a wooden telephone pole

Bird nesting box on a wooden telephone pole

Insect nesting box, insect hotel

Barn Owl (Tyto alba), young in nest box hissing, Rio Grande Valley, Texas, USA