John Shaw / Great frigatebird (Fregata minor) male at nest site, with gular sac inflated to attract females. Genovesa Island, Galapagos, May.

Ingo Arndt / Golden Bosun / Tropicbird (Phaethon lepturus fulvus) in flight, endemic to Christmas Island, Indian Ocean, Australian Territory, November

Tui De Roy / Red-billed tropicbird (Phaethon aethereus) in flight over water. Galapagos Islands, Ecuador, May.

Tui De Roy / Red-billed tropicbird (Phaethon aethereus) in flight. Galapagos Islands, Ecuador.

Michael Pitts / Red tailed tropic bird flying, Midway Atoll, Pacific Ocean

Michael Pitts / Red tailed tropic bird with chick, Midway Atoll, Pacific Ocean

Michael Pitts / Red tailed tropic bird adult with chick, Midway Atoll, Pacific Ocean

John Cancalosi / Red tailed tropicbird {Phaethon rubricauda} in flight, Antigua, West Indies

Charlie Summers / Golden bosun bird (Phaethon lepturus fulvus) flying over settlement on Christmas Island, Australia.

John Shaw / Red-billed tropicbird (Phaethon aethereus) in flight. Espanola Island, Galapagos, May.

Nick Hawkins / Red-billed tropicbird (Phaethon aethereus) in flight. San Cristobal Island, Galapagos.

Nick Hawkins / Red billed tropicbird (Phaethon aethereus) in flight. San Cristobal Island, Galapagos.