Tui De Roy / Great frigatebird (Fregata minor) male guarding single chick. Punta Cevallos, Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Great frigatebird (Fregata minor) male taking flight at dusk. Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Magnificent frigatebirds (Fregata magnificens) in low flight ovehead. Espanola Island, Galapagos, Ecuador, December.

Cheryl-Samantha Owen / Great frigate birds (Fregata minor) sitting in tree, Aldabra Atoll, Seychelles, Indian Ocean

Ole Jorgen Liodden / Magnificent Frigatebird (Fregata magnificens) male displaying, red throat pouch inflated. Galapagos

Ole Jorgen Liodden / Magnificent Frigatebird (Fregata magnificens)displaying in flight, red pouch inflated. Galapagos

Kevin Schafer / Ascension frigatebird (Fregata aquila) male soaring high, Ascension island, Atlantic Ocean, Vulnerable species

Kevin Schafer / Ascension frigatebird (Fregata aquila) flock soaring high, Ascension island, Atlantic Ocean, Vulnerable species

Tui De Roy / Great Frigatebird (Fregata minor) female guarding chick, Galapagos Islands, Ecuador

Gerrit Vyn / Adult male Magnificent Frigatebird (Fregata magnificens) displaying. Dry Tortugas NP, Florida, USA

Patrick Morris / Magnificent frigate bird {Frigata magnificens} pair on nest, male displaying with red throat pouch inflated, Genovesa Is, Galapagos

Pete Oxford / Great frigate bird (Fregata minor) female on nest with chick, Galapagos

Pete Oxford / Great frigatebird (Fregata minor) male displaying, pouch inflated, Galapagos

Tui De Roy / Great Frigatebird (Fregata minor) courting males vying for female's attention, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) recently formed pair, female inspecting male in courtship display with extended gular pouch, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male with inflated gular pouch in courtship display, Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) pair courting, male in full display with inflated gular air pouch, Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with fully inflated gular air pouch, Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) recently formed pair, female inspecting male in courtship display with extended gular pouch, Genovesa Tower Island, Galapagos Islands, Ecuador

Pete Oxford / Great frigate bird (Fregeta minor) male with pouch fully inflated. Orgenoves Island, Galapagos

Pete Oxford / Great Frigate bird (Fregeta minor) male courtship display. Galapagos, Tower Orgenoves Island

Pete Oxford / Great frigate bird feeding chick {Fregata minor} Genovesa, Galapagos.

John Cancalosi / Magnificent frigatebird {Fregeta magnificens} male courtship display, Antigua, West Indies

Mike Wilkes / Young Great Frigatebird (Fregata minor) perched on rock. Genovesa, Galapagos Islands.

Mike Wilkes / Great Frigatebirds (Fregata minor) in flight silhouetted against sky. Genovesa, Galapagos Islands.

Mike Wilkes / Great Frigatebirds (Fregata minor) in flight silhouetted against blue sky. Genovesa, Galapagos Islands.

Mike Wilkes / Great Frigatebird (Fregata minor) in flight against blue sky. Genovesa, Galapagos Islands.

Mike Wilkes / Great Frigatebird (Fregata minor) male (with red pouch) and female at nest. Genovesa, Galapagos Islands.

Mike Wilkes / Great Frigatebird (Fregata minor) female sunbathing. Genovesa, Galapagos Islands.

Mike Wilkes / Great Frigatebird (Fregata minor) displaying by inflating its gular pouch. Genovesa, Galapagos Islands.

Mark MacEwen / Lesser Frigatebird (Fregata ariel) adult head portrait, Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird (Fregata ariel) adult head portrait profile, Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird juvenile (Fregata ariel) Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird male (Fregata ariel) Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird (Fregata ariel) male in flight, Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird (Fregata ariel) male collecting nesting material, Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird (Fregata ariel) juvenile in flight, Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird (Fregata ariel) juveniles in flight, Raine Island National Park, Great Barrier Reef, Australia.

Mark MacEwen / Lesser Frigatebird (Fregata ariel) adult in flight, Raine Island National Park, Great Barrier Reef, Australia.

Christophe Courteau / Male Great frigate bird displaying {Fregata minor} Galapagos

Christophe Courteau / Male Great frigate bird in flight, vocal sac visible {Fregata minor} Galapagos.

Christophe Courteau / Female Great frigate bird nesting {Fregata minor} Galapagos.

Christophe Courteau / Male Great frigate bird displaying {Fregata minor} Galapagos.

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) parent coming into land at nest with waiting chick, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) female and chick at nest on top of shrub near beach, chick begging for food, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) female and chick at nest on top of shrub near beach, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) parent coming into land at nest with waiting chick, 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 / Lesser frigatebird (Fregata ariel) nesting on top of shrub with Red tailed tropicbird (Phaethon rubicauda) nesting directly on ground below, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) chick portrait, covered in downy white feathers to protect from heat of sun, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) chick calling to parents, white feathers are to protect from heat of sun, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) parent arriving back to chick at nest, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebirds (Fregata ariel) brooding on nests on top of shrub, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) adult with chick in tree top nest, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) female and chick at nest on top of shrub near beach, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) chicks are covered with white feathers to protect themselves from the heat of the sun, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) chick at nest, covered in white feathers as protection against heat of sun, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) female sheltering chick from harsh sunlight, shading with wing, in nest on top of shrub near beach, Christmas Island, Indian Ocean, July

Yukihiro Fukuda / Lesser frigatebird (Fregata ariel) parent coming into land at nest with waiting chick, Christmas Island, Indian Ocean, July

Christian Ziegler / Magnificent Frigatebird (Fregata magnificens) breeding colony on small mangrove island, Carrie Bow Cay, Belize

Donald M. Jones / Magnificent Frigatebird (Fregata magnificens) displaying male with inflated gular air pounch and female at nest site, Sian Ka'an Biosphere Reserve, Mexico

Donald M. Jones / Magnificent Frigatebird (Fregata magnificens) juvenile, Sian Ka'an Biosphere Reserve, Mexico

Donald M. Jones / Magnificent Frigatebird (Fregata magnificens) pair flying, Sian Ka'an Biosphere Reserve, Mexico

Donald M. Jones / Magnificent Frigatebird (Fregata magnificens) flock flying, Sian Ka'an Biosphere Reserve, Mexico

Donald M. Jones / Magnificent Frigatebird (Fregata magnificens) picking up nesting material in mid-flight, Sian Ka'an Biosphere Reserve, Mexico

Donald M. Jones / Magnificent Frigatebird (Fregata magnificens) flock flying, Sian Ka'an Biosphere Reserve, Mexico

Tui De Roy / Great frigatebird (Fregata minor) male with calling chick on nest. Espanola Island, Galapagos, Ecuador, May.

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

Tui De Roy / Great frigatebird (Fregata minor) male brooding his chick on nest. Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Great frigatebird (Fregata minor) male brooding his chick on nest. Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Magnificent frigatebirds (Fregata magnificens) in courtship behaviour, males inflating red gular pouches and females (white bib) observing. Espanola Island, Galapagos, Ecuador, June.

Tui De Roy / Magnificent frigatebirds (Fregata magnificens) flying overhead in formation against fluffy white clouds. Espanola Island, Galapagos, Ecuador, June.

Tui De Roy / Great frigatebird (Fregata minor) male on nest with chick in white plumage. Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Great frigatebird (Fregata minor) on nest with chick in white plumage. Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Great frigatebird (Fregata minor) male with inflated gular pouch as courtship display. Genovesa Island, Galapagos, Ecuador, June.

Tui De Roy / Great frigatebird (Fregata minor) male in flight with inflated gular pouch in courtship display. Genovesa Island, Galapagos, June.

Tui De Roy / Great frigatebird (Fregata minor) female incubating egg as male grooms her. Espanola Island, Galapagos, Ecuador, May.

Tui De Roy / Great frigatebird (Fregata minor) on nest with chick in white plumage. Espanola Island, Galapagos, Ecuador, May.

Alex Mustard / Frigate bird (Fregata minor) soaring in formation around the moon at sunset, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.

Steve Gettle / Magnificent Frigatebird (Fregata magnificens) male calling, Galapagos Islands, Ecuador

Steve Gettle / Magnificent Frigatebird (Fregata magnificens) male stealing food from Red-billed Tropicbird (Phaethon aethereus), Galapagos Islands, Ecuador

Steve Gettle / Magnificent Frigatebird (Fregata magnificens) pair, Galapagos Islands, Ecuador

Steve Gettle / Magnificent Frigatebird (Fregata magnificens) male displaying with gular pouch fully inflated, Galapagos Islands, Ecuador

Steve Gettle / Magnificent Frigatebird (Fregata magnificens) pair flying, Galapagos Islands, Ecuador

Steve Gettle / Magnificent Frigatebird (Fregata magnificens) male displaying with gular pouch fully inflated, Galapagos Islands, Ecuador

Ole Jorgen Liodden / Magnificent Frigatebird (Fregata magnificens) male displaying. Galapagos

Ole Jorgen Liodden / Magnificent Frigatebird (Fregata magnificens) in flight. Panned action, Galapagos

Mark Carwardine / Magnificent Frigatebird (Fregata magnificens) male inflating neck pouch to attract a mate. January.

Christian Ziegler / Magnificent Frigatebird (Fregata magnificens) breeding colony on a small mangrove island, Carrie Bow Cay, Belize

Pete Oxford / Magnificent Frigatebird (Fregata magnificens) perching on a mangrove branch. Sian Ka'an Biosphere Reserve, Quintana Roo, Yucatan Peninsula, Mexico.

Pete Oxford / Magnificent Frigatebirds (Fregata magnificens) in flight over mangrove trees. Sian Ka'an Biosphere Reserve, Quintana Roo, Yucatan Peninsula, Mexico.

Pete Oxford / Magnificent Frigatebirds (Fregata magnificens) in flight over mangrove trees. Sian Ka'an Biosphere Reserve, Quintana Roo, Yucatan Peninsula, Mexico.

Pete Oxford / Magnificent Frigatebird (Fregata magnificens) silhouetted in flight. Sian Ka'an Biosphere Reserve, Quintana Roo, Yucat‡n Peninsula, Mexico.

Brent Stephenson / Great Frigatebird (Fregata minor) male in flight against a blue sky, showing underwing and deflated throat-pouch. Ducie Island, Pitcairn Group, September.

Brent Stephenson / Lesser Frigatebird (Fregata ariel) male in flight, showing underwing. Mataiva, Tuamotus, French Polynesia, September.

Brent Stephenson / Great Frigatebird (Fregata minor) male in flight, showing underwing and deflated throat pouch. Motu Tunga, Tuamotus, French Polynesia, November.