"Sterna (T.) caspia. Caspian Tern. Imperial Tern. Bill dark vermilion red, growing and somewhat "diaphanous"…
"Sterna (T.) maxima. Cayenne Tern. Royal Tern. Adult in summer: Pileum glossy greenish-black, not extending…
"Sterna (T.) cantiaca. Sandwich Tern. Ducal Tern. Bill black, the tip 1/2 to 3/4 an inch bright yellow,…