Anup Shah / Celebes / Black crested macaque (Macaca nigra) sub-adult male trying to break into bamboo to feed on ant eggs from a nest, Tangkoko National Park, Sulawesi, Indonesia.

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Yukihiro Fukuda / Male Japanese giant salamander (Andrias japonicus) protecting his eggs inside his nest, Japan, October

Yukihiro Fukuda / Male Japanese giant salamander (Andrias japonicus) protecting his eggs inside his nest, Japan, September

Roger Powell / Stone curlew (Burhinus oedicnemus) approaching nest of two eggs, Guerreiro, Castro Verde, Alentejo, Portugal, April

Tui De Roy / Sparkling violetear hummingbird (Colibri coruscans) incubating eggs at nest, Andean cloud forest, Ecuador

Ernie Janes / Hedge sparrow / Dunnock (Prunella modularis) nest with three eggs, nest exposed in hedge by summer hedge cutting, UK

Diane McAllister / Newly hatched Western scrub jay chicks (Aphelocoma californica) huddling together in their nest near one last egg. This nest is in a backyard in Reno. Nevada, USA, June

Alex Hyde / Helmet Vanga (Euryceros prevostii) on nest incubating eggs. Masoala Peninsula National Park, north east Madagascar. IUCN Vulnerable Species.

Nick Upton / Great Crane Project team members Beate Blahy and Roland Digby inspecting Eurasian / Common crane eggs (Grus grus) in reed pool nest in Germany before collecting them for UK reintroduction programme. S...

Wild Wonders of Europe / Radisic / Whiskered tern (Chlidonias hybrida) on nest with two eggs, Lake Skadar, Lake Skadar National Park, Montenegro, May 2008

Michel Poinsignon / Little ringed plover {Charadrius dubius} nest with four eggs camouflaged on shingle, Lorraine, France

Wild Wonders of Europe / Lesniewski / Stone curlew (Burhinus oedicnemus) by nest, Bagerova Steppe, Kerch Peninsula, Crimea, Ukraine, July 2009

Wild Wonders of Europe / Radisics / Whiskered tern (Chlidonias hybrida) on nest with two eggs, wings stretched, Lake Skadar, Lake Skadar National Park, Montenegro, May 2008

Wild Wonders of Europe / Radisic / Two Whiskered terns (Chlidonias hybrida) in flight near nest with two eggs, Lake Skadar, Lake Skadar National Park, Montenegro, May 2008. Exclusive Japanese calendar rights for 2014

Pete Oxford / Black-browed Albatross (Thalassarche melanophrys) nesting colony, Steeple Jason Island, Falkland Islands

Wild Wonders of Europe / Shpilenok / Demoiselle crane (Anthropoides virgo) tending two eggs in its nest, Cherniye Zemli (Black Earth) Nature Reserve, Kalmykia, Russia, May 2009

Michel Poinsignon / Great crested grebe (Podiceps cristatus) returning to eggs on nest with chicks on back, Lorraine, France

Kim Taylor / European Starling (Sturnus vulgaris) parent flying from nest hole carrying eggshell. Surrey, UK

Hanne & Jens Eriksen / Two Wood pigeon {Columba palumbus} eggs in nest, Sayq Plateau, Oman

Michael Quinton / Great Gray Owl (Strix nebulosa) parent protecting eggs in nest, North America

Michael Quinton / Great Gray Owl (Strix nebulosa) incubating eggs on nest, North America

John Waters / Mute Swan {Cygnus olor} female on nest tending newly hatched chick and eggs, Somerset, UK.

John Waters / Mute Swan {Cygnus olor} female on nest, rolling eggs, Somerset, UK.

Tom Vezo / Green heron with eggs on nest {Butorides virescens} Mexico

Juan Manuel Borrero / Audouin's gull newly hatched chick and eggs in nest {Ichthyaetus audouinii} Delta del Ebro NP, Spain Catalonia

Tom Vezo / Least tern {Sternula antillarum} on nest, Long Island, USA.

Tom Vezo / Least tern {Sternula antillarum} eggs in nest, Long Island, USA.

Tom Vezo / Herring gull {Larus argentatus} eggs in nest, Newfoundland, Canada.

Mitsuaki Iwago / Green Sea Turtle (Chelonia mydas) female laying eggs in nest on beach, endangered, Hawaii

Michael & Patricia Fogden / Common Egg-eating Snake (Dasypeltis scabra) swallowing egg from another animal's nest, savannah, South Africa

Rolf Nussbaumer / Lesser nighthawk female with egg at nest {Chordeiles acutipennis} Texas, USA.

Tom Vezo / Piping Plover (Charadrius melodus) sitting on eggs in nest on ground, Long Island, New York

Gerry Ellis / Magnificent Hummingbird (Eugenes fulgens) nest with three eggs, Costa Rica

Flip de Nooyer / Common Eider (Somateria mollissima) adult female at down nest with eggs, Europe

Sumio Harada / American Robin (Turdus migratorius) newly-hatched day old chicks begging in nest with unhatched blue egg, Glacier National Park, Montana

Gerry Ellis / Greater Flamingo (Phoenicopterus ruber) nesting colony with mud nests, Inagua National Park, Bahamas

Konrad Wothe / Kentish Plover (Charadrius alexandrinus) male at nest, Europe

Jim Brandenburg / Western Grebe (Aechmophorus occidentalis) nest with egg floating in prairie pothole, Aberdeen, South Dakota

Michael Quinton / Red-necked Grebe (Podiceps grisegena) parent on nest with eggs in boreal pond, Alaska

Tui De Roy / Blue-footed Booby (Sula nebouxii) male incubating eggs with webbed feet, Seymour Island, Galapagos Islands, Ecuador

Mitsuaki Iwago / Loggerhead Sea Turtle (Caretta caretta) female laying eggs in nest in beach sand, Australia

Michael Quinton / Canada Goose (Branta canadensis) hatchlings in nest with unhatched eggs, spring, Idaho

Michael Quinton / Common Loon (Gavia immer) chick with hatching egg in nest in the summer, Wyoming

Mitsuaki Iwago / Loggerhead Sea Turtle (Caretta caretta) hatchling emerging from underground nest on sandy beach, Australia

John Cancalosi / Mallee fowl male working nest mound. Eggs are laid in mound and incubated by 'composting' heat of vegetation in mound. Temperature regulated by adding or removing material by adults. Australia

John Cancalosi / Stone curlew (Burhinus oedicnemus) at nest with eggs. UK

John Cancalosi / Reed warbler's nest with eggs and European cuckoo chick just hatched, UK

Chris Gomersall / Avocet incubating eggs at nest {Recurvirostra avosetta}, at dusk, Suffolk, England UK

WILLIAM OSBORN / Canada goose sitting on eggs at nest {Branta canadensis} Wiltshire England UK

Jabruson / Red billed quelea eggs inside nest {Quelea quelea} Tsavo East NP, Kenya

Tony Heald / Male African jacana caring for chick and eggs {Actophilornis africana} Chobe NP, Botswana

Juergen Freund / Green turtle laying eggs in nest on beach {Chelonia mydas} Sulawesi, Indonesia

John Cancalosi / Canada Goose (Branta canadensis) in defensive posture over nest with mate in background. New York state, USA, May.

Staffan Widstrand / Polar Bear (Ursus maritimus) feeding on eggs possibly taken from Skua's nest, Svalbard, Norway, July

Paul Hobson / Red throated diver (Gavia stellata) incubating eggs on nest, Iceland June

Paul Hobson / Red throated diver (Gavia stellata) incubating eggs on nest, Iceland June

Paul Hobson / Avocet (Recurvirostra avosetta) at nest with eggs, Texel, Holland, May

Fiona Rogers / Celebes / Black crested macaque (Macaca nigra) sub-adult male trying to break into bamboo to feed on ant eggs from a nest, Tangkoko National Park, Sulawesi, Indonesia.

Anup Shah / African harrier hawk (Polyboroides typus) investigating a cavity to see if there is a nest to steal eggs from, Masai Mara National Reserve, Kenya. March

Mark MacEwen / Broad snouted caiman (Caiman latirostris) young emerging from the nest, Sante Fe, Argentina

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Mark MacEwen / Broad snouted caiman (Caiman latirostris) hatching from egg in nest, Sante Fe, Argentina, February

Mark MacEwen / Broad snouted caiman (Caiman latirostris) eggs in nest, Sante Fe, Argentina, February

Mark Carwardine / Cook Strait / Common / Northern tuatara (Sphenodon punctatus) wild nest burrow with eggs, Karori Sanctuary, Wellington, New Zealand, endangered species, endemic

Steven David Miller / Emu (Dromaius novaehollandiae) eggs in nest, Northern Territory Wildlife Park, Darwin, Australia

Loic Poidevin / Black winged stilt (Himantopus himantopus) nest and eggs raised above water, Breton Marsh, West France, June

Scott Leslie / Snapping Turtle (Chelydra serpentina) nest cavity with eggshells, Canada

Yukihiro Fukuda / Wedgetailed shearwater (Puffinus pacificus) exposed egg in nest that is underground, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Red tailed tropicbird (Phaethon rubicauda) incubating eggs at nest near beach, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) solitary egg in nest on top of shrub, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Red tailed tropicbird (Phaethon rubicauda) incubating eggs at nest near beach, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Masked booby (Sula dactylatra) both parents take turns to brood eggs on ground nest, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Masked booby (Sula dactylatra) returning to brood solitary egg on ground nest, Christmas Island, Indian Ocean, July

Todd Mintz / Semipalmated plover (Charadrius semipalmatus) eggs and nest, Grise Fiord, Ellesmere Island, Nunavut, Canadian Arctic, June

Donald M. Jones / Ruffed Grouse (Bonasa umbellus) eggs in nest at base of tree, Troy, Montana

Donald M. Jones / Ruffed Grouse (Bonasa umbellus) eggs in nest at base of tree, Troy, Montana

Yukihiro Fukuda / Male Japanese giant salamander (Andrias japonicus) protecting his eggs inside his nest, Japan, September

Yukihiro Fukuda / Japanese giant salamander (Andrias japonicus) in nest with eggs containing developing embryos, Japan, October

Yukihiro Fukuda / Male Japanese giant salamander (Andrias japonicus) protecting his eggs inside his nest, Japan, September

Yukihiro Fukuda / Pair of Japanese giant salamanders (Andrias japonicus) at the entrance to their nest, spawning, Japan, September

Yukihiro Fukuda / Pair of Japanese giant salamanders (Andrias japonicus) at the entrance to their nest, spawning, Japan, September

Yukihiro Fukuda / Pair of Japanese giant salamanders (Andrias japonicus) at the entrance to their nest, spawning, Japan, September

Yukihiro Fukuda / Pair of Japanese giant salamanders (Andrias japonicus) at the entrance to their nest, spawning, Japan, September

Alan Williams / Kittiwake (Rissa tridactyla) at nest on cliff with egg, Puffin Island, North Wales UK June

Roger Powell / Stone curlew (Burhinus oedicnemus) at nest of two eggs, Guerreiro, Castro Verde, Alentejo, Portugal, April

Roger Powell / Stone curlew (Burhinus oedicnemus) pair changing over incubation duties at the nest, Guerreiro, Castro Verde, Alentejo, Portugal, April

Tui De Roy / Great frigatebird (Fregata minor) female incubating egg as male tends to the nest. Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Brown pelican (Pelecanus occidentalis) on nest incubating eggs with beach and other bird in flight. Santa Cruz Island, Galapagos, Ecuador, June.

Roger Powell / Common guillemot (Uria aalge) pair at nest, one about to incubate an egg while the other watches, Great Saltee Island, Wexford, Republic of Ireland, June

Roger Powell / Common guillemot (Uria aalge) pair at nest, one about to incubate an egg while the other watches, Great Saltee island, Wexford, Republic of Ireland, June