Onychoprion, the "brown-backed terns", is a genus of seabirds in the family Laridae. 
The genus name is from Ancient Greek onux, "claw" or "nail", and prion, "saw".

1/ Bridled tern (Nhàn lưng đen, Onychoprion anaethetus)
The specific anaethetus means "senseless, stupid".

2/ Sooty tern (Nhàn nâu, Onychoprion fuscatus), coloquially wideawake tern or just wideawake
The specific fuscatus is Latin for "dark".