Adult female kelp goose (Chloephaga hybrida) in the Falkland Islands

Adult rockhopper penguins (Eudyptes chrysocome chrysocome) at breeding and molting colony on New Island, Falkland Islands

Adult rockhopper penguins (Eudyptes chrysocome chrysocome) at breeding and molting colony on New Island, Falkland Islands

Magellanic penguin (Spheniscus magellanicus) at a breeding and molting site in Estancia San Lorenzo, Argentina

Northern gannet (Morus bassanas) breeding colony at the cliffs of Noss, Shetland Islands, Scotland, United Kingdom

Adult whooper swan (Cygnus cygnus), pair on nest near Lake Myvatn, Iceland

Adult whooper swan (Cygnus cygnus), pair on nest near Lake Myvatn, Iceland

Caspian Tern (Hydroprogne caspia) at breeding colony on Ile des Oiseaux in the Parc National du Delta du Saloum, UNESCO World Heritage Site, Senegal, West Africa, Africa

King penguin (Aptenodytes patagonicus) chicks (okum boys) at breeding colony at Gold Harbour, South Georgia, Polar Regions

Adult black-legged kittiwake (Rissa tridactyla) in aerial combat against another kittiwake near Alexander Island, Russia, Eurasia

Adult chinstrap penguin (Pygoscelis antarctica), breeding colony at Half Moon Island, Antarctica, Southern Ocean, Polar Regions

King penguin (Aptenodytes patagonicus) breeding and nesting colony at Salisbury Plain in the Bay of Isles, South Georgia, Southern Ocean, Polar Regions

Hamerkop (Scopus umbretta) carrying nesting material, Zimanga Game Reserve, South Africa, Africa

King penguin (Aptenodytes patagonicus) breeding and nesting colony on South Georgia Island, Southern Ocean, Polar Regions

Adult rockhopper penguins (Eudyptes chrysocome chrysocome) at breeding and molting colony on New Island, Falkland Islands

Adult dovekie (Alle alle alle) breeding area on the island of Bolscheoya in the Svalbard Archipelago, Norway

Adult arctic tern (Sterna paradisaea) male bringing female a fish, Spitsbergen Island in the Svalbard Archipelago, Norway

Brunnichs guillemots (Uria lomvia) in flight at Cape Fanshawe in the Svalbard Archipelago, Norway

Adult southern rockhopper penguins (Eudyptes chrysocome), at breeding colony on West Point Island, Falklands, South America

Southern elephant seal (Mirounga leonina) mating behavior on South Georgia Island, Southern Ocean

Adult rockhopper penguin (Eudyptes chrysocome chrysocome) at breeding and molting colony on New Island, Falkland Islands

Adult king penguins (Aptenodytes patagonicus) amongst chicks at breeding colony at Gold Harbour, South Georgia Island, Polar Regions

Bull moose (Alces alces) wades through the mist of a cool Southcentral Alaska evening during the September 'rut', or breeding season. Moose are the largest member of the deer family. The animals are circumpolar and the Alaska-Yukon race, Alces alces gigas, is the largest of all, Alaska, United States of America

Portrait of a bull moose (Alces alces) walking through an alpine meadow late in the rut in Southcentral Alaska's Chugach State Park, Alaska, United States of America

Bull moose (Alces alces) is startled as a jealous cow threatens a competitor during the rut, or breeding season, in Southcentral Alaska's Chugach State Park, USA, Alaska, United States of America

Close-up portrait of a male willow ptarmigan (Lagopus lagopus) showing early breeding colors in its neck and eye combs, surveying its high-country territory in Southcentral Alaska's Chugach Mountains on an April day. The head and neck will become completely chocolate-brown as the bird's breeding colors develop, Alaska, United States of America

Bull moose (Alces alces) pauses late in the rut in South-central Alaska's Chugach State Park, Anchorage, Alaska, United States of America

Approached by a cow moose, a bull (Alces alces), displays the Flehmen response late in the rut in Southcentral Alaska's Chugach State Park, Anchorage, Alaska, United States of America

Alaska bull moose (Alces alces) patrols a marsh during the rut, or fall breeding season, in mid-September, Anchorage, Alaska, United States of America