Sandwich tern 白嘴端燕鸥
The Sandwich tern (Thalasseus sandvicensis) is a seabird of the tern family, Sternidae. It is very closely related to the lesser crested tern (T. bengalensis), Chinese crested tern (T. bernsteini), Cabot's tern (T. acuflavidus), and elegant tern (T. elegans) and has been known to interbreed with the lesser crested.