Marie Read / Red-legged kittiwake (Rissa brevirostris) in breeding plumage perched on narrow cliff ledge, St. Paul, Pribilof Islands, Alaska, USA. July.

Marie Read / Two Red-legged kittiwakes (Rissa brevirostris) in breeding plumage, perched on a rock in water, one calling and raising wings aggressively at the other, St. Paul, Pribilof Islands, Alaska, USA. August...

Marie Read / Red-legged kittiwake (Rissa brevirostris) in breeding plumage perched on rock, St. Paul, Pribilof Islands, Alaska, USA. August.

Marie Read / Three Red-legged kittiwakes (Rissa brevirostris) and a Black-legged kittiwake (Rissa tridactyla) perched on a rock along the shore, St. Paul, Pribilof Islands, Alaska, USA. August.

Marie Read / Pine grosbeak (Pinicola enucleator) male, perched on branch feeding on Ash (Fraxinus sp.) seeds in winter, Burlington, Vermont, USA. February.

Marie Read / Group of Parakeet auklets (Aethia psittacula) perched on rock ledge, competing for space to roost, St. Paul, Pribilof Islands, Alaska, USA. July.

Marie Read / Pine grosbeak (Pinicola enucleator) male, feeding on Spruce (Picea sp.) buds in late winter, Burlington, Vermont, USA. February.

Marie Read / Pacific wren (Troglodytes pacificus) Bering Sea race, male, perched on Cow parsnip (Heracleum maximum) singing, St. Paul, Pribilof Islands, Alaska, USA. July.

Marie Read / Pacific loon (Gavia pacifica) in breeding plumage, on water with reflection, Anchorage, Alaska, USA. May.

Marie Read / Pacific loons (Gavia pacifica) pair in breeding plumage, on water, Anchorage, Alaska, USA. May.

Marie Read / Parakeet auklet (Aethia psittacula) in flight over water, with a bulging throat pouch, full of food for chicks, St. Paul, Pribilof Islands, Alaska, USA. August.

Marie Read / Northern parula (Parula americana) male in breeding plumage, singing while perched on flowering Eastern redbud (Cercis canadensis) in spring, Ohio, USA. April.

Marie Read / Northern parula (Parula americana) male in breeding plumage, perched on branch singing in spring, Ohio, USA. April.

Marie Read / Northern parula (Parula americana) male in breeding plumage, perched on flowering Eastern redbud (Cercis canadensis) in spring, Ohio, USA. April.

Marie Read / Horned puffin (Fratercula corniculata) resting on small ledge amid yellow lichen-encrusted rocks, St. Paul, Pribilof Islands, Alaska, USA. July.

Marie Read / Group of Horned puffins (Fratercula corniculata) perched on cliff face, St. Paul, Pribilof Islands, Alaska, USA. August.

Marie Read / Group of Horned puffins (Fratercula corniculata) perched on cliff face, St. Paul, Pribilof Islands, Alaska, USA. August.

Marie Read / Hooded warbler (Wilsonia citrina) male, perched on branch singing in spring, Ohio, USA. April.

Marie Read / Green-winged teal (Anas crecca) male, in flight over a marshland pool, Alaska, USA. May.

Marie Read / Crested auklets (Aethia cristatella) pair interacting while perched on lichen-covered rocks, St. Paul, Pribilof Islands, Alaska, USA. July.

Marie Read / Crested auklets (Aethia cristatella) pair interacting while perched on lichen-covered rocks, St. Paul, Pribilof Islands, Alaska, USA. July.

Marie Read / Green-winged teal (Anas crecca) male, in flight over a marshland pool, Alaska, USA. May.

Marie Read / Bobolink (Dolichonyx oryzivorus) male, in flight over Dandelion (Taraxacum sp.) flowers in a meadow, New York, USA. May.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) chick resting on feet of adult, Atka Bay, Antarctica. (NON-EX.)

Emmanuel Rondeau / Purple heron (Ardea purpurea) using a wildlife crossing above the A72 highway, Loire, France. June. Camera trap image.

Emmanuel Rondeau / Ring-necked pheasant (Phasianus colchicus) walking along a wildlife underpass below the A89 highway and above the Deirot river, Correze, France. September. Camera trap image.

Joel Sartore / Photo Ark / American robin (Turdus migratorius migratorius) portrait. The tail of this bird was pulled off by a cat. Wild Bird Rehabilitation Inc., St. Louis, Missouri, USA. Captive.

Joel Sartore / Photo Ark / American robin (Turdus migratorius propinquus) portrait, Wildlife Rehabilitation Center of Northern Utah, USA. Captive.

Joel Sartore / Photo Ark / Newfoundland robin (Turdus migratorius nigrideus) portrait, Carolina Waterfowl Rescue, North Carolina, USA. Captive.

Pal Hermansen / King eiders (Somateria spectabilis), Eiders (Somateria mollissima) and Gulls (Larus sp.) in fishing harbour. During the winter time the birds gather in harbour to feed on fish waste, Batsfjord, Finnma...

Pal Hermansen / King eider (Somateria spectabilis) on water in fishing harbour, Batsfjord, Finnmark, Norway. February.

Pal Hermansen / Eurasian cranes (Grus grus) flock in flight in v-formation, migrating south, Germany. November.

Pal Hermansen / Eurasian cranes (Grus grus) flock in flight in v-formation, migrating south, Germany. November.

Pal Hermansen / Starling (Sturnus vulgaris) perched on table at outdoor restaurant with people behind, Hyde Park, London, England, UK. October.

Pal Hermansen / Starling (Sturnus vulgaris) flock roosting in tree at dusk, Tonder, Denmark. October.

Pal Hermansen / Mallard ducks (Anas platyrhynchos) flock in winter, portrait, Oslo, Norway. December.

Pal Hermansen / Eurasian cranes (Grus grus) flock in flight in double v-formation above houses during migration, Lunen village, Germany. October.

Pal Hermansen / Great spotted woodpecker (Dendrocopos major) perched on electricity pole, picking seeds from a pine cone stashed in the wooden pole, Germany. October.

Pal Hermansen / Starling (Sturnus vulgaris) flock in flight, Hyde Park, London, England, UK. October.

Pal Hermansen / Starling (Sturnus vulgaris) head portrait, Hyde Park, London, England, UK. October.

Pal Hermansen / Starling (Sturnus vulgaris) head portrait, Hyde Park, London, England, UK. October.

Pal Hermansen / Group of Starlings (Sturnus vulgaris) feeding on food scraps left on plates at an outdoor restaurant, Hyde Park, London, England, UK. October.

Pal Hermansen / Greylag goose (Anser anser) resting with head tucked under wing, Hyde Park, London, England, UK. October.

Pal Hermansen / White-tailed eagle (Haliaeetus albicilla) fishing, Trondelag, Norway. September.

Pal Hermansen / Black-headed weaver (Ploceus melanocephalus) building its nest, Masai Mara, Kenya.

Pal Hermansen / Willow grouse (Lagopus lagopus) male, display flight, against blue sky, Hardangervidda mountain plateau, Norway. June.

Pal Hermansen / Two Eurasian cranes (Grus grus) walking across frozen lake, Varmland, Sweden. April.

Pal Hermansen / Two Whooping swans (Cygnus cygnus) on misty river in freezing temperatures at dawn, Golsfjell, Viken, Norway. February.

Pal Hermansen / Dipper (Cinclus cinclus) perched on rock in frozen river, Follo, Norway. February.

Pal Hermansen / Bearded reedling (Panurus biarmicus) male, in flight among reeds, Oslo fjord, Viken, Norway. February.

Pal Hermansen / Bearded reedling (Panurus biarmicus) male, landing among reeds, Oslo fjord, Viken, Norway. February.

Pal Hermansen / Sunbittern (Eurypyga helias) wading in river, Costa Rica.

Pal Hermansen / Two Red-billed pigeons (Patagioenas flavirostris) portrait, Costa Rica.

Pal Hermansen / Montezuma oropendulas (Psarocolius montezuma) pair, male feeding female during courtship, Costa Rica.

Pal Hermansen / Prong-billed barbet (Semnornis frantzii) head portrait, Costa Rica.

Pal Hermansen / Black-mandibled toucan (Ramphastos ambiguus) head portrait, Costa Rica.

Pal Hermansen / Green heron (Butorides virescens) perched on wooden post calling, Costa Rica.

Pal Hermansen / Goosander (Mergus merganser) male, taking flight from water in snowfall, Trondelag, Norway. March.

Pal Hermansen / Emperor penguin (Aptenodytes forsteri) colony on snow, adults with chicks in penguin "kindergarten", Snow Hill island, Antarctica.

Mateusz Piesiak / Drone tracking shot of Whooper swan (Cygnus cygnus) flock flying above braided glacial river, Iceland. June.

Mateusz Piesiak / Drone tracking shot of Whooper swan (Cygnus cygnus) flock flying above braided glacial river, Iceland. June.

Mateusz Piesiak / Drone tracking shot of Whooper swan (Cygnus cygnus) flock flying above braided glacial river, Iceland. June.

Mateusz Piesiak / Drone tracking shot of Great cormorant (Phalacrocorax carbo) resting on edge of ice on glacial river, south Iceland. February.

Mateusz Piesiak / Aerial shot of Gull (Larus sp.) flock near braided glacial river, south Iceland. June.

Mateusz Piesiak / Aerial tracking shot of Gull (Larus sp.) flock near braided glacial river, south Iceland. June.

Lucas Bustamante / Tawny-bellied screech owl (Megascops watsonii) perched at entrance to nest hole in tree cavity, Yasuni National Park, Orellana, Ecuador.

Lucas Bustamante / Flightless cormorant (Nannopterum harrisi) standing on the shore spreading its wings, Fernandina Island, Galapagos National Park, Galapagos Islands.

Lucas Bustamante / Ocellated turkey (Meleagris ocellata) male, portrait, Gallon Jug, Orange Walk District, Belize.

Lucas Bustamante / Galapagos flamingo (Phoenicopterus ruber glyphorhynchus) portrait, Floreana Island, Galapagos National Park, Galapagos Islands.

Lucas Bustamante / Gentoo penguin (Pygoscelis papua) chasing away a Brown skua (Stercorarius antarcticus), Antarctic Peninsula, Antarctica.

Lucas Bustamante / Marine iguanas (Amblyrhynchus cristatus) and Blue-footed boobies (Sula nebouxii) resting on lava rocks along the shore, Isabela Island, Galapagos National Park, Galapagos Islands.

Lucas Bustamante / Gentoo penguin (Pygoscelis papua) resting in the snow, Antarctic Peninsula, Antarctica.

Franco Banfi / Great potoo (Nyctibius grandis) perched in tree, Pantanal wetlands, Mato Grosso, Brazil.

Franco Banfi / Cocoi heron (Ardea cocoi) fishing in river, Pantanal wetlands, Mato Grosso, Brazil.

Franco Banfi / Cocoi heron (Ardea cocoi) in flight carrying fish prey in beak, Pantanal wetlands, Mato Grosso, Brazil.

Franco Banfi / RF - Great potoo (Nyctibius grandis) perched in tree, Pantanal wetlands, Mato Grosso, Brazil. (This image may be licensed either as rights managed or royalty free.)

Andy Sands / Common snipe (Gallinago gallinago) perched on fence post calling, Upper Teesdale, County Durham, England, UK. July.

Andy Sands / Red grouse (Lagopus lagopus scotica) male, standing on rock on moorland, North Yorkshire, England, UK. July.

Andy Sands / Golden plover (Pluvialis Apricaria) male, perched among burnt stems of heather on moorland, North Yorkshire, England, UK. July.

Andy Sands / Golden plover (Pluvialis Apricaria) chick standing among grasses on moorland, North Yorkshire, England, UK. July.

Andy Sands / RF - Sedge warbler (Acrocephalus schoenobaenus) male, perched on dead twigs singing, Yorkshire, England, UK. June. (This image may be licensed either as rights managed or royalty free.)

Andy Sands / RF - Sedge warbler (Acrocephalus schoenobaenus) male, perched on dead twigs singing, Yorkshire, England, UK. June. (This image may be licensed either as rights managed or royalty free.)

Andy Sands / Hazel (Corylus avellana) close up of female flower with pollen grains, Hertfordshire, England, UK. February. Focus stacked.

Andy Sands / Grasshopper warbler (Locustella naevia) perched on branch with caterpillar prey in beak, returning to feed young in nest, Bedfordshire, England, UK. June.

Andy Sands / Grasshopper warbler (Locustella naevia) perched on Wild rose stem singing, Bedfordshire, England, UK. June.

Andy Sands / Grasshopper warbler (Locustella naevia) perched on Wild rose stem singing, Bedfordshire, England, UK. June.

Andy Sands / Grasshopper warbler (Locustella naevia) perched on Wild rose stem, Bedfordshire, England, UK. June.

Andy Sands / Common snipe (Gallinago gallinago) standing among Sedges, Upper Teesdale, County Durham, England, UK. June.

Andy Sands / Common snipe (Gallinago gallinago) feeding in frost-covered Watercress (Nasturtium officinale) bed in winter, Hertfordshire, England, UK. December

Robin Chittenden / Monk parakeets (Myiopsitta monachus) pair peering from nest, Park Guell, Barcelona, Spain. August.

Robin Chittenden / Carrion crow (Corvus corone) caught inside a Larson trap on moorland, Scottish Highlands, Scotland, UK. April.

Robin Chittenden / Carrion crow (Corvus corone) caught inside a Larson trap on moorland, Scottish Highlands, Scotland, UK. April.

Robin Chittenden / Two Monk parakeets (Myiopsitta monachus) perched on branch, Park Guell, Barcelona, Spain. August.

Robin Chittenden / Monk parakeet (Myiopsitta monachus) perched on branch, Park Guell, Barcelona, Spain. August.

Robin Chittenden / Common waxbill (Estrilda astrild) perched on branch with pink flowers, Barcelona, Spain. August.

Robin Chittenden / Common waxbill (Estrilda astrild) perched on branch with pink flowers, Barcelona, Spain. August.