David Woodfall / Little tern (Sterna albifrons) nest with three eggs in shingle ridge. County Wicklow, Republic of Ireland, June.

David Woodfall / Two Little terns (Sterna albifrons) at the nest amongst Black oats (Avena strigosa) growing on shell rich sands Machair, North Uist, Scotland, UK, June.

David Woodfall / Little tern (Sterna albifrons) at the nest amongst Black oats (Avena strigosa) growing on shell rich sands Machair, North Uist, Scotland, UK, June.

David Woodfall / Little tern (Sterna albifrons) with newly hatched chick, Gronant dunes, Denbighshire, Wales, UK, June.

David Woodfall / Little tern (Sterna albifrons ) feeding sand eel (Hyperoplus spp) to young chick. Gronant Dunes, Denbighshire, Wales, UK, June.

John Chan / Juvenile California least tern (Sternula antillarum browni) begging for food from a decoy, used to attract breeding pairs to deserted nest sites, Huntington Beach, California, USA, June.

John Chan / California least tern chick (Sternula antillarum browni) falling over as it runs towards its parent returning to nest site, Huntington Beach, California, USA, June.

John Chan / Male California least tern (Sternula antillarum browni) presenting fish offering to female during mating, Huntington Beach, California, USA, May.

Pedro Narra / Little Tern (Sterna albifrons) feeding chick, Sado Estuary, Portugal. June

John Chan / Male California Least Tern (Sternula antillarum browni) courting a female, presenting a fish before chasing off another male, Huntington Beach, California, USA, May.

Sebastian Kennerknecht / White Tern (Gygis alba) flying over beach, Midway Atoll, Hawaiian Leeward Islands, Hawaii

Sebastian Kennerknecht / White Tern (Gygis alba) chick, Midway Atoll, Hawaiian Leeward Islands, Hawaii