Hanne & Jens Eriksen / Caspian tern (Hydroprogne caspia) with open beak, in shallow water. Oman, March.

John Chan / Caspian tern (Hydroprogne caspia) plunge diving near a group of Elegant terns (Thalasseus elegans) gathering at breeding grounds, Southern California, USA, March.

Jussi Murtosaari / Caspian tern (Hydroprogne caspia) with fish prey, Finland, April.

Andy Trowbridge / Caspian Tern (Sterna caspia) in flight. Lake Forsyth, Banks Peninsula, Canterbury, New Zealand. August.

Andy Trowbridge / Caspian Tern (Sterna caspia) in flight. Ashley River, Canterbury, New Zealand. August.

Hanne & Jens Eriksen / Caspian tern (Hydroprogne caspia) in flight looking for food, Oman, August

Hanne & Jens Eriksen / Caspian tern (Hydroprogne caspia) in flight with fish, Oman, November

Claudio Contreras / Caspian tern (Sterna caspia) in flight, El Vizcaino Biosphere Reserve, Baja Califonia Peninsula, Mexico, May

Hanne & Jens Eriksen / Caspian tern (Hydroprogne caspia) juvenile calling for food from adult, Oman, February.

Mike Wilkes / Caspian tern (Sterna caspia) catching fish, Tanji Beach, Gambia, West Africa.

Mike Wilkes / Caspian terns (Sterna caspia) resting on beach, Tanji Beach, Gambia, West Africa.

Mike Wilkes / Caspian tern (Sterna caspia) catching fish, Tanji Beach, Gambia, West Africa.

Mike Wilkes / Caspian tern (Sterna caspia) feeding on fish, Tanji Beach, Gambia, West Africa.

Mike Wilkes / Caspian tern (Sterna caspia) flying over beach, Tanji Beach, Gambia, West Africa.

Hanne & Jens Eriksen / Caspian tern (Sterna caspia) in flight, Oman, January

Loic Poidevin / Caspian terns (Hydroprogne caspia), British Columbia, Canada, June.

LYNN M. STONE / Royal Terns (Thalasseus maximus) in foreground with Caspian Tern (Sterna caspia) pair in background, note much more slender, more orange bills of Royal Terns, in breeding plumage, on shoreline of Tamp...

Robin Chittenden / Caspian Tern (Sterna / Hydroprogne caspia) in flight over waves, The Gambia

Onne van der Wal / Caspian terns (Hydroprogne caspia, formerly Sterna caspia), flying off the coast of Belize.

Robin Chittenden / Caspian tern (Sterna caspia) in flight. Hickling Broad NWT, Norfolk, UK. May.

Andy Trowbridge / Caspian Tern (Sterna caspia) in flight, diving for prey. Lake Ellesmere, Canterbury, South Island, New Zealand.

Jussi Murtosaari / Caspian tern (Hydroprogne caspia) in flight. Kikkosalmi, Finland. May.

Marie Read / Caspian terns (Sterna caspia), aggressive interaction between adult (facing viewer) and juvenile, Cayuga Lake, Ithaca, New York, USA, August.

Marie Read / Caspian terns (Sterna caspia), juvenile (left) begging from adult in late summer, Cayuga Lake, Ithaca, New York, USA, August.

Marie Read / Caspian terns (Sterna caspia), adult arrives with fish to feed begging juvenile, late summer, Cayuga Lake, Ithaca, New York, USA, August.

Bernard Castelein / Caspian tern (Sterna caspia) flying with shell in beak, probably a juvenile play fishing objects from water surface. Allahein River, Gambia.

Bernard Castelein / Caspian tern (Sterna caspia) flying over water. Allahein River, Gambia.

Bernard Castelein / Caspian tern (Sterna caspia) stretching wings before taking off. Allahein River, Gambia.