Least Tern (Sternula antillarum) – A tiny, pale tern with a black-capped head and yellow bill; rare spring and summer visitor, usually at lakes or reservoirs in southern Arizona, often during breeding season dispersal.
Gull-billed Tern (Gelochelidon nilotica) – Medium-sized tern with a thick black bill and buoyant flight; very rare spring and summer migrant, occasionally lingering at large wetlands or flooded fields.
Black Tern (Chlidonias niger) – Small, dark-bodied marsh tern, adults strikingly black in breeding plumage; rare but regular spring and fall migrant through inland lakes, ponds, and wetlands.
Common Tern (Sterna hirundo) – Slender, long-tailed tern with red bill tipped black; rare migrant, primarily in late summer and fall at large reservoirs.
Common Tern
Arctic Tern (Sterna paradisaea) – Similar to Common Tern but with shorter bill, longer tail streamers, and buoyant flight; accidental in Arizona, usually during spring or fall migration, often associated with storms.
Royal Tern (Thalasseus maximus) – Large, orange-billed coastal tern; extremely rare vagrant, typically seen after hurricanes or strong tropical systems, often near large reservoirs.
Royal Tern