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"Sterna (T.) maxima. Cayenne Tern. Royal Tern. Adult in summer: Pileum glossy greenish-black, not extending below eyes, so narrow on side of upper mandible that a broad white streak extends to extreme tip of the feathers. Mantle exceedingly light pearl-blue, fading imperceptibly into white on the rump and towards the extremities of the tertials. Tail white, with a faint tinge of pearly, especially on the central feathers and inner webs of the other. Secondaries pure white for their whole length except a small space on the outer web near the tip, which is grayish-blue, deeper than the mantle. Outer web of first primary grayish-black; in the inner web of the same has a space of black extending the whole length of the feather, very narrow at the base, widening as it runs toward the tip. within 1 & 1/2 inches of which it occupies the whole web; the rest of the web white. separated from the black by a straight distinct line of division. The second, third, fourth, and fifth primaries have the same general characteristics, but the white space grows narrow and shorter, and round up further in the centre than along the edge of the web, so that for a little way from its end it has a border of blackish along its outer margin; other primaries wholly pearl-blue, their inner webs margined with white. Bill coral and orange-red, with a slightly lighter tip; feet blackish, their soles dull yellowish." Elliot Coues, 1884

Royal Tern

"Sterna (T.) maxima. Cayenne Tern. Royal Tern. Adult in summer: Pileum glossy greenish-black, not extending…