Tern
Ad. in summer. -Top of the head and nape black; back and wings pale pearl-gray; outer web of outer primaries silvery; tip and shaft part of the inner web darker; inner part of the inner web, except for a narrow mar- TERNS. gin at the end of the feather, white; tail white, slightly forked, the middle feathers grayish; under parts white; bill and feet black, the former rather short and stout. Ad. in winter.-Similar to the above, but top of the head white, auriculars grayish, and a space in front of the eye blackish. L., 14:50 ; W., 12.00; T., 5.50; B., 1·40; depth of B. at base, 50.