David Fleetham / African / Jackass penguin (Spheniscus demersus) colony at Boulders Beach, Simons Town, Cape Town, Western Cape, South Africa.

Bernard Castelein / Grey heron ( Ardea cinerea) perched on a tree branch, Peerdsbos, Brasschaat, Belgium, April.

Bernard Castelein / Black woodpecker (Dryocopus martius) pecking at tree trunk, Peerdsbos, Brasschaat, Belgium, April.

Bernard Castelein / Adult male Great spotted woodpecker (Dendrocopops major) feeding a juvenile, Brasschaat, Belgium, June.

Bernard Castelein / Adult male Great spotted woodpecker (Dendrocopos major) at water drinking, Brasschaat, Belgium, June.

Bernard Castelein / Adult male Greenfinch (Carduelis chloris) feeding a begging chick, Brasschaat Belgium, July.

Bernard Castelein / Female Greenfinch (Carduelis chloris) drinking, Brasschaat Belgium, July.

Bernard Castelein / Male Greenfinch (Carduelis chloris) perched on branch, Brasschaat Belgium, July.

Bernard Castelein / Female Blackbird (Turdus merula) collecting nesting material, Brasschaat, Belgium, May.

Bernard Castelein / Song Trush (Turdus philomelos) collecting nesting material, Brasschaat, Belgium, May.

Jack Dykinga / Burrowing owl (Athene cunicularia) chick and parent perched on ground, chick begging parent for food, Marana, Arizona, USA.

Jack Dykinga / Burrowing owl (Athene cunicularia) parent and three chicks on ground. Parent feeding chick, Marana, Arizona, USA.

Jack Dykinga / Burrowing owl (Athene cunicularia) parent and three chicks on ground, one chick with beetle in mouth, Marana, Arizona, USA.

Jack Dykinga / Burrowing owl (Athene cunicularia) female eating chick during stressful period in the Sonoran Desert; of five chicks only one remains, Marana, Arizona, USA.

Jack Dykinga / Burrowing owl (Athene cunicularia) female and three chicks. Female with remains of her fourth chick in mouth which she has been eating, Marana, Arizona, USA.

Jack Dykinga / Crested caracara (Caracara plancus) wading in flooded field searching for prey, Marana irrigated farm fields, Marana, Arizona, USA.

Jack Dykinga / Crested caracara (Caracara plancus) in flooded field with pack rat in its mouth, The Caracara delivers a spine severing bite killing its prey instantly, Marana irrigated farm fields, Marana, Arizona,...

Jack Dykinga / Crested caracara (Caracara plancus) in flooded field with a pack rat in its mouth, crouched ready to fly, Marana irrigated farm fields, Marana, Arizona, USA.

Jack Dykinga / Crested caracara (Caracara plancus) taking off from flooded field with pack rat in beak, Marana irrigated farm fields, Marana, Arizona, USA.

Jack Dykinga / Burrowing owl (Athene cunicularia) female perched on telephone line against a large super-moon at moonrise, Marana irrigated farm fields, Marana, Arizona, USA.

Oscar Dewhurst / Shelduck (Tadorna tadorna) landing on water. Gloucestershire, England, UK. March

Oscar Dewhurst / Shelduck (Tadorna tadorna) landing on water. Gloucestershire, England, UK. March

Oscar Dewhurst / Tufted duck (Aythya fuligula) male swimming. Gloucestershire, England, UK. March

Oscar Dewhurst / Northern pintail (Anas acuta) pair in flight. Gloucestershire, England, UK. March

Oscar Dewhurst / Eurasian teal (Anas crecca) male flapping its wings. Gloucestershire, England, UK. March

Oscar Dewhurst / Black-headed gull (Chroicocephalus ridibundus) pair courting. Gloucestershire, England, UK. March

Oscar Dewhurst / Rook (Corvus frugilegus) standing on short grass. Gloucestershire, England, UK. March

Oscar Dewhurst / Rook (Corvus frugilegus) standing on short grass. Gloucestershire, England, UK. March

Oscar Dewhurst / Robin (Erithacus rubecula) singing in woodland, backlit. Bristol, England, UK. March

Oscar Dewhurst / Starling (Sturnus vulgaris) murmuration over the Somerset Levels. Somerset, England, UK. January

Oscar Dewhurst / Starling (Sturnus vulgaris) murmuration over the Somerset Levels. Somerset, England, UK. January

Oscar Dewhurst / Starling (Sturnus vulgaris) murmuration over the Somerset Levels. Somerset, England, UK. January

Oscar Dewhurst / Blue tit (Cyanistes caeruleus) perched on reed head. Suffolk, England, UK. September

Oscar Dewhurst / Little egret (Egretta garzetta) wading in water at sunrise. Suffolk, England, UK. September

Oscar Dewhurst / Little egret (Egretta garzetta) in flight. Suffolk, England, UK. September

Oscar Dewhurst / Peregrine falcon (Falco peregrinus) at regular perching site in disused quarry. Somerset, England, UK. August

Oscar Dewhurst / European robin (Erithacus rubecula) perched on branch. London, England, UK. December

Oscar Dewhurst / Mute swan (Cygnus olor) swimming. Richmond Park, London, England, UK. December

Oscar Dewhurst / Mute swan (Cygnus olor) swimming. Richmond Park, London, England, UK. December

Oscar Dewhurst / Mute swan (Cygnus olor) swimming through ice. Richmond Park, London, England, UK. December

Oscar Dewhurst / Eurasian kestrel (Falco tinnunculus) juvenile perched on grass mound. Richmond Park, London, England, UK. June

Oscar Dewhurst / Eurasian kestrel (Falco tinnunculus) spreading out wings in the dust. Richmond Park, London, England, UK. June.

Oscar Dewhurst / Eurasian kestrel (Falco tinnunculus) juveniles perched on grass mound. Richmond Park, London, England, UK. June

Oscar Dewhurst / Eurasian kestrel (Falco tinnunculus) juvenile perched on log. Richmond Park, London, England, UK. June

Oscar Dewhurst / Mute swan (Cygnus olor) adult swimming on a misty lake, backlit at sunrise. Richmond Park, London, England, UK. May

Oscar Dewhurst / Reed bunting (Emberiza schoeniclus) male singing from bracken fern. Richmond Park, London, England, UK. May

Oscar Dewhurst / Mute swan (Cygnus olor) cygnets swimming. London, England, UK. May

Oscar Dewhurst / Nuthatch (Sitta europaea) feeding on tree trunk. Forest of Dean, Gloucestershire, England, UK. March.

Oscar Dewhurst / Nuthatch (Sitta europaea) looking at hole in tree, potential nest site, Forest of Dean, Gloucestershire, England, UK. March

Oscar Dewhurst / Grey wagtail (Motacilla cinerea) male perched on a low-hanging branch, Forest of Dean, Gloucestershire, England, UK. March

Oscar Dewhurst / Northern pintail (Anas acuta) male swimming. Gloucestershire, England, UK. March

Oscar Dewhurst / Northern pintail (Anas acuta) male displaying in water. Gloucestershire, England, UK. March

Oscar Dewhurst / Northern pintails (Anas acuta) in flight. Gloucestershire, England, UK. March

Colin Varndell / Germander speedwell (Veronica chamaedrys) in flower. Dorset, UK May

John Cancalosi / Gila woodpecker (Melanerpes uropygialis) feeding on Saguaro (Carnegiea gigantea) blossom nectar and the insects trapped in them, Sonoran Desert, Arizona, USA.

John Cancalosi / Curve-billed thrasher (Toxostoma curvirostre) feeding on Saguaro cactus (Carnegiea gigantea) blossom nectar and the insects trapped in it, Sonoran Desert , Arizona, USA.

John Cancalosi / Curve-billed thrasher (Toxostoma curvirostre) feeding on Saguaro cactus(Carnegiea gigantea) blossom nectar and the insects trapped in it, Sonoran Desert, Arizona, USA.

John Cancalosi / Gilded flicker (Colaptes chrysoides) feeding on Saguaro cactus (Carnegiea gigantea) blossom nectar, Sonoran Desert, Arizona, USA.

John Cancalosi / Curve-billed thrasher (Toxostoma curvirostre) feeding on nectar in Saguaro cactus (Carnegiea gigantea) blossom and the insects trapped in them, Sonoran Desert, Arizona, USA.

John Cancalosi / Gila woodpecker (Melanerpes uropygialis) pair feeding on Saguaro cactus (Carnegiea gigantea) blossom nectar, one chasing the other off the blossoms, Sonoran Desert, Arizona, USA.

John Cancalosi / Gilded flicker (Colaptes chrysoides) feeding on Saguaro cactus (Carnegiea gigantea) blossom nectar and exotic House sparrow (Passer domesticus) by nest; the most widely distributed wild bird on the pl...

John Cancalosi / Curve-billed thrasher (Toxostoma curvirostre) on Saguaro cactus (Carnegiea gigantea) calling from perch on top of flowers, Sonoran Desert, Arizona, USA.

John Cancalosi / Harris hawk (Parabuteo unicinctus) parent visiting nest in Saguaro cactus (Carnegiea gigantea) with Spiny lizard (Sceloporus sp.) in beak. Juvenile hawk about to fledge, Sonoran desert, Arizona, USA.

John Cancalosi / Harris hawk (Parabuteo unicinctus) parent visiting nest in Saguaro cactus (Carnegiea gigantea) with desert rabbit for juvenile about to fledge, Sonoran Desert, Arizona, UK.

John Cancalosi / Gila woodpecker (Melanerpes uropygialis) pair at nest entrance in Saguaro cactus (Carnegiea gigantea) one adult flying from nest, Sonoran Desert, Arizona, USA.

John Cancalosi / Gilded flicker (Colaptes chrysoides) feeding on Saguaro cactus (Carnegiea gigantea) blossom nectar, Sonoran Desert, Arizona, USA.

John Cancalosi / Gilded flicker (Colaptes chrysoides) feeding on Saguaro cactus (Carnegiea gigantea) blossom nectar, Sonoran desert, Arizona, USA.

John Cancalosi / Gilded flicker (Colaptes chrysoides) feeding on Saguaro cactus (Carnegiea gigantea) blossom nectar, Sonoran Desert, Arizona, USA.

John Cancalosi / Gila woodpecker (Melanerpes uropygialis) flying from nest in Saguaro cactus (Carnegiea gigantea) with fecal sac, Sonoran Desert, Arizona, USA.

John Cancalosi / Gila woodpecker (Melanerpes uropygialis) feeding on Saguaro (Carnegiea gigantea) blossom nectar, Sonoran Desert, Arizona, USA.

John Cancalosi / Harris hawk (Parabuteo unicinctus) parent visiting nest in Saguaro cactus (Carnegiea gigantea) Juvenile hawk about to fledge, Sonoran Desert, Arizona, USA.

John Cancalosi / Great horned owl (Bubo virginianus) adult and chick in nest in Saguaro cactus (Carnegiea gigantea) Sonoran Desert, Arizona, USA.

John Cancalosi / Harris hawk (Parabuteo unicinctus) juvenile in nest in Saguaro cactus (Carnegiea gigantea) practicing flying, Sonoran Desert, Arizona, USA.

John Cancalosi / Mourning dove (Zenaida macroura) adult and squab on nest in Cholla cactus (Cylindropuntia sp.) Sonoran Desert, Arizona, USA.

John Cancalosi / Mourning dove (Zenaida macroura) adult and squab on nest in Cholla cactus (Cylindropuntia sp.) Sonoran Desert, Arizona, USA.

John Cancalosi / Gila woodpecker (Melanerpes uropygialis) leaving nest cavity in Saguaro cactus (Carnegiea gigantea) with fecal sac, Sonoran Desert, Arizona, USA.

Pascal Tordeux / Golden eagle (Aquila chrysaetos) in flight over mountains, Queyras, France

Charlie Summers / Great horned owl (Bubo virginianus) two chicks looking out of nest cavity in tree. Chicks are just over four weeks old and starting to lose their white fluff, Eastern Arapahoe County, Colorado, USA.

Charlie Summers / Cape weaver (Ploceus capensis) male hanging upside down peering into nest entrance as he starts to attract a female, Bavianskloof, Eastern Cape Province, South Africa.

Charlie Summers / American kestrel (Falco sparverius) flying with snake in talons, Elbert County, Colorado, USA.

Charlie Summers / Great horned owl chick (Bubo virginianus) with juvenile plumage in tree cavity nest, Eastern Arapahoe County, Colorado, USA.

Charlie Summers / Pied-billed grebe (Podilymbus podiceps) pair on pond, one with offering for mate, North Park, Colorado, USA.

Charlie Summers / Great horned owl chick (Bubo virginianus) with juvenile coloration in nest in hollow cottonwood tree by highway, Eastern Arapahoe County, Colorado, USA.

Charlie Summers / Gabar goshawk (Micronisus gabar) bathing in rainwater puddle in sandy road, Nossob Road, Kgalagadi Transfrontier Park, South Africa.

Inaki Relanzon / Leucistic Gentoo penguin (Pygoscelis papua) Falkland Islands

Inaki Relanzon / Black-crowned night heron (Nycticorax nycticorax falklandicus) Pebble island, Falklands.

Inaki Relanzon / Gentoo penguins (Pygoscelis papua) pair, Sea Lion Island, Falkland Islands.

Inaki Relanzon / Imperial Shag (Phalacrocorax atriceps albiventer) colony, Falkland Islands.

Inaki Relanzon / Black-browed albatross (Thalassarche melanophris) pair, courtship, Falkland Islands.

Inaki Relanzon / Black-browed albatross (Thalassarche melanophris) pair in courtship, Falkland Islands.

Inaki Relanzon / King penguins (Aptenodytes patagonicus) chick portrait, Falkland Islands.

Inaki Relanzon / Gentoo penguin (Pygoscelis papua) surfing the waves, Sea Lion Island, Falkland Islands.

Inaki Relanzon / Megallenic penguin (Spheniscus magellanicus) near nesting site, Falkland Islands.

Inaki Relanzon / Southern rockhopper penguin, (Eudyptes chrysocome chrysocome) pair courtship behaviour silhouetted, Falkland Islands.

Inaki Relanzon / Megallenic penguins (Spheniscus magellanicus), at sunrise Falkland Islands.

Inaki Relanzon / King penguins (Aptenodytes patagonicus) group walking along beach in front of wave, Falkland Islands.