860-291953 - Southern Carmine Bee-eater (Merops nubicoides), on the cliff of the Luangwa river, Luangwa river, South Luangwa natioinal Park, Zambia

860-291952 - Southern Carmine Bee-eater (Merops nubicoides), on the cliff of the Luangwa river, Luangwa river, South Luangwa natioinal Park, Zambia, Africa

860-291951 - Southern Carmine Bee-eater (Merops nubicoides), on the cliff of the Luangwa river, a white-fronted bee-eater (Merops bullockoides) hold the tail' feathers, Luangwa river, South Luangwa natioinal Park, Zambia, Africa

860-291950 - Southern Carmine Bee-eater (Merops nubicoides), on the cliff of the Luangwa river, Luangwa river, South Luangwa natioinal Park, Zambia,

832-401299 - European green woodpecker (Picus viridis), male at nest hole feeding the young, Biosphere Reserve, Swabian Alb, Baden-Wuerttemberg, Germany, Europe

832-401298 - European green woodpecker (Picus viridis), male at nest hole feeding the young, Biosphere Reserve, Swabian Alb, Baden-Wuerttemberg, Germany, Europe

832-401245 - Common starling (Sturnus vulgaris), old bird feeding young bird at the breeding cavity, Hesse, Germany, Europe

832-401244 - Common starling (Sturnus vulgaris), adult bird approaching breeding cavity with food in its beak, Hesse, Germany, Europe

860-291220 - Big colony of the bee-eaters (Merops apiaster) in their burrows on a clay wall. Africa. Uganda.

860-291379 - Little owl (Athena noctua) peeking from his hole, England

860-291221 - Big colony of the bee-eaters (Merops apiaster) in their burrows on a clay wall. Africa. Uganda.

832-397244 - Raccoon (Procyon lotor), fawn looking out of its tree hollow, Hesse, Germany, Europe

832-397245 - Raccoon (Procyon lotor), young and fawn looking out of their tree den, Hesse, Germany, Europe

860-290888 - Tengmalm's Owl (Aegolius funereus) in a lodge dug in a beech tree by a black woodpecker, Massif des Bauges, France

832-396056 - Young little owls (Athene noctua) at the breeding tube, Emsland, Lower Saxony, Germany, Europe

832-394613 - Insect hotel, bee hotel, Waiblingen, Baden-Wuerttemberg, Germany, Europe

832-393979 - Beehive, artificial nesting box for honey bees, Baden-Wuerttemberg, Germany, Europe

860-290141 - Hoopoe (Upupa epops) flying near its lodge with a spider in its beak to feed a young in spring, Country garden around Toul, Meurthe-et-Moselle, France

860-290154 - European Bee-eater (Merops apiaster) adult bringing a bumblebee to the nest , May, South France

860-289816 - Magellanic penguin (Spheniscus magellanicus) at his nesting hole, Volunteer Point, East Falkland, Falklands

860-290147 - Great Spotted Woodpecker (Dendrocopos major) getting her head out of her dressing room ready to take off, June, France

860-290142 - Hoopoe (Upupa epops) in flight near its lodge with a larva in the beak to feed a young in spring, Country garden near Toul, Meurthe-et-Moselle, France

832-393005 - Common starling (Sturnus vulgaris) flies to breeding cavity, North Rhine-Westphalia, Germany, Europe

832-393007 - Common starling (Sturnus vulgaris) feeding young bird at breeding cavity, North Rhine-Westphalia, Germany, Europe

832-393089 - Middle spotted woodpecker (Dendrocopos medius), looking out of breeding cavity, North Rhine-Westphalia, Germany, Europe

832-393090 - Middle spotted woodpecker (Dendrocopos medius), with food in its beak at the breeding cavity, North Rhine-Westphalia, Germany, Europe

832-393006 - Common starling (Sturnus vulgaris) feeding young bird at breeding cavity, North Rhine-Westphalia, Germany, Europe

832-392100 - Tawny owl (Strix aluco), adult bird looking out of a tree cavity, Frankfurt, Hesse, Germany, Europe

832-391988 - European green woodpecker (Picus viridis) leaves breeding cavity, Neunkirchen im Siegerland, North Rhine-Westphalia, Germany, Europe

832-390655 - Middle spotted woodpecker (Dendrocopos medius) at nest hole, feeding young bird, Lower Saxony, Germany, Europe

832-390753 - Young hawk owl (Strix uralensis), looking out of the breeding hole, Bavarian Forest, Germany, Europe

832-390751 - Young hawk owl (Strix uralensis), looking out of the breeding hole, Bavarian Forest, Germany, Europe

832-390677 - Puffin (Fratercula arctica), breeding den, Hornoya, Varanger, Norway, Europe

832-390654 - Middle spotted woodpecker (Dendrocopos medius) looking out of nest hole, Lower Saxony, Germany, Europe

832-390538 - Blue tit (Cyanistes caeruleus) looking out of the entrance hole of the breeding cavity, Moenchbruch nature reserve, Moerfelden, Hesse, Germany, Europe

832-390021 - Southern carmine bee-eater (Merops nubicoides), Crimson pint looking out of breeding cave, Zambia, Africa

832-389502 - Tawny owl (Strix aluco) in front of its burrow, Hesse, Germany, Europe

832-389503 - Tawny owl (Strix aluco) in front of its burrow, Hesse, Germany, Europe

832-388759 - Hoopoe (Upupa epops) feeding young bird, Middle Elbe Biosphere Reserve, Saxony-Anhalt, Germany, Europe

832-388663 - African penguin (Spheniscus demersus), adult, looks from breeding cave, beach, on land, Boulders Beach, Simon's Town, Western Cape, South Africa, Africa

832-386537 - Hoopoe (Upupa epops), adult bird feeds young birds at the breeding cave in the tree, worm in the beak, Saxony-Anhalt, Germany, Europe

860-288362 - Green woodpecker (Picus viridis) young head coming out of the nest hole, England

832-379237 - Hoopoe (Upupa epops) with feed at brood cave, Kiskunsag National Park, Hungary, Europe

832-378946 - Hoopoe (Upupa epops) with food at brood-cave, backlight, biosphere reserve Mittelelbe, Saxony-Anhalt, Germany, Europe

832-379236 - Hoopoe (Upupa epops) approaching Breeding Cave, National Park Kiskunsag, Hungary, Europe

832-379235 - White-backed woodpecker (Dendrocopos leucotos), female with food in the beak at the nesting hole, Bukk National Park, Hungary, Europe

832-378945 - Hoopoe (Upupa epops) with Blue-winged grasshopper (Oedipoda caerulescens) as food, young birds feeding at brood cave, Biosphere Reserve Mittelelbe, Saxony-Anhalt, Germany, Europe

860-282568 - Young Sand Martins landing to nest burrow, Finland

860-285557 - Female Grey-headed woodpecker and chicks at nest, Finland

860-282297 - Southern Yellow-billed Hornbills, Kruger NP South Africa

860-285555 - Female Grey-headed woodpecker and chicks at nest, Finland

860-285553 - Male Grey-headed woodpecker at nest, Finland

860-285554 - Male Grey-headed woodpecker and chick at nest, Finland

860-284647 - Black woodpecker feeding chicks, Offendorf Alsace France

860-282571 - Sand Martin landing to nest burrow, Finland

860-285551 - Male Grey-headed woodpecker looking out of nest hole-Finland

860-285552 - Male Black Woodpecker at nest, Finland

832-372945 - European hornets (Vespa crabro), workers on the entrance to the nest, former nesting hole of a great spotted woodpecker, Thuringia, Germany, Europe

832-367330 - Black woodpecker (Dryocopus martius), male sitting at the entrance of its nesting hole, Neunkirchen, Siegerland, North Rhine-Westphalia, Germany, Europe

832-374969 - Great Spotted Woodpecker or Greater Spotted Woodpecker (Dendrocopos major), with insects in its beak at the nesting hole, Rhineland-Palatinate, Germany, Europe

832-369715 - Little Owl (Athene noctua), approaching nesting hole

832-367686 - Black Woodpecker (Dryocopus martius) at nest hole in a beech with chicks (Fagus sylvatica), Biosphaerenreservat Schwaebische Alb or Swabian Mountains Biosphere Reserve, UNESCO World Heritage Site, Baden-Wuerttemberg, Germany, Europe

832-369716 - Little Owl (Athene noctua) approaching nesting hole with prey, Bitburg, Rhineland-Palatinate, Germany, Europe

832-369717 - Little Owl (Athene noctua) approaching nesting hole with prey, Bitburg, Rhineland-Palatinate, Germany, Europe

832-367684 - Black Woodpecker (Dryocopus martius) at nest hole in a beech with chick (Fagus sylvatica), Biosphaerenreservat Schwaebische Alb or Swabian Mountains Biosphere Reserve, UNESCO World Heritage Site, Baden-Wuerttemberg, Germany, Europe

832-369727 - Great Spotted Woodpecker (Dendrocopos major), Bitburg, Rhineland-Palatinate, Germany, Europe

832-367341 - Spotted Owlet (Athene brama), Ranthambore National Park, Rajasthan, India, Asia

832-374968 - Great Spotted Woodpecker or Greater Spotted Woodpecker (Dendrocopos major), with insects in its beak at the nesting hole, Rhineland-Palatinate, Germany, Europe

832-372950 - Northern hawk owl (Surnia ulula), female with prey perched at the nesting hole, Finland, Europe

832-367342 - Spotted Owlet (Athene brama) in a tree hole, Ranthambore National Park, Rajasthan, India, Asia

832-367328 - Green Woodpecker (Picus viridis), male at the entrance to nisting hole, Neunkirchen, Siegerland, North Rhine-Westphalia, Germany, Europe

832-367343 - Two Spotted Owlets (Athene brama) staring from their tree hole in Ranthambore Tiger Reserve, Ranthambore National Park, Rajasthan, India, Asia

832-367685 - Black Woodpecker (Dryocopus martius) at nest hole in a beech with chicks (Fagus sylvatica), Biosphaerenreservat Schwaebische Alb or Swabian Mountains Biosphere Reserve, UNESCO World Heritage Site, Baden-Wuerttemberg, Germany, Europe

1161-3941 - Great Spotted Woodpecker makes nesting hole in Poplar tree , Hampstead, London, United Kingdom

1161-3942 - Great Spotted Woodpecker makes nesting hole in Poplar tree , Hampstead, London, United Kingdom

869-2563 - hoopoe hoopoe with food flying in front of the nesting hole feeding young portrait

971-45 - Leatherback turtle (Dermochelys coriacea) excavating a nest hole, Shell Beach, Guyana, South America

1024-221 - Great spotted woodpecker (Dendrocopos major) at nest hole, UK

1024-222 - Great spotted woodpecker (Dendrocopos major) excavating nest hole, UK

1024-220 - Great spotted woodpecker (Dendrocopos major) at nest hole, UK

995-35 - Black Guillemot (Cepphus grylle) sitting in a drain pipe that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-33 - Black Guillemot (Cepphus grylle) sitting in a drain pipe that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-25 - Black Guillemot (Cepphus grylle) standing in a drain pipe that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll Scotland, UK

995-29 - Black Guillemot (Cepphus grylle) sitting in a wall that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-31 - Black Guillemot (Cepphus grylle) pair sitting in a drain pipe that they are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-28 - Black Guillemot (Cepphus grylle) calling while sitting in a wall that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-30 - Black Guillemot (Cepphus grylle) pair standing in a drain pipe that they are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-32 - Black Guillemot (Cepphus grylle) calling while sitting in a drain pipe that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-26 - Black Guillemot (Cepphus grylle) sitting in a drain pipe that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-27 - Black Guillemot (Cepphus grylle) standing in a wall that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll, Scotland, UK

995-23 - Black Guillemot (Cepphus grylle) pair sitting in a drain pipe that they are nesting in, one bird is calling. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll Scotland, UK

995-24 - Black Guillemot (Cepphus grylle) calling while sitting in a wall that a pair are nesting in. Black Guillemots nest in drains and holes in the sea wall in the middle of Oban town centre. Argyll Scotland, UK

832-8842 - Elf Owl (Micrathene whitneyi), adult in nest hole in telephone pole, Madera Canyon, Tucson, Arizona, USA

832-8071 - Barred Owl (Strix varia), young in nesting cavity, Raleigh, Wake County, North Carolina, USA

832-8816 - Golden-fronted Woodpecker (Melanerpes aurifrons), male at nesting cavity in palm tree, Brownsville, Rio Grande Valley, South Texas, USA

832-8003 - Eastern Screech-Owl (Megascops asio), adult in hole in mesquite tree camouflaged, Willacy County, Rio Grande Valley, Texas, USA

832-8929 - Ferruginous Pygmy-Owl (Glaucidium brasilianum), young looking out of nesting cavity, Willacy County, Rio Grande Valley, South Texas, USA

832-8413 - Eastern Screech-Owl (Megascops asio, Otus asio), adult roosting in hole in mesquite tree, camouflaged, Willacy County, Rio Grande Valley, South Texas, USA

832-2011 - Green Woodpecker (Picus viridis), male feeding callow