BIRDS OF NORTH AND MIDDLE AMERICA. 489 
coverts and broad tips to secondaries, immaculate white; bill yellow 
with a broad subterminal band or area of black; iris dark brown; 
legs and feet brownish in dried skin (said to be orange-yellow or dull 
orange in life). 
Adults in winter.—Similar to summer adults, but stripe on side 
of head more grayish, especially the postocular portion, and (espe- 
cially in fresh plumage) the silvery frosting on primaries more pro- 
nounced. 
Immature (young in first winter ?).—Similar to winter adults, but 
under parts pure white instead of pale gray, primariés darker, and 
bill more dusky or browoish, only the tip being distinctly yellow. 
Young.—‘‘The patch before and the streak behind the eye decid- 
edly larger, and there is an indication of a grayish crescent on the 
nape; the crown grayish white, slightly mottled with brown, as are 
the feathers of the mantle; tail-feathers dark ash-gray with white 
margins; bill yellowish brown at the base, the rest blackish, with no 
yellow at the tip; tarsi and toes yellow.” @ 
Adult male—Wing, 264; tail, 140; exposed culmen, 38.5; tarsus 
22; middle toe, 21.° 
Coast of southern South America, from Brazil (Rio de Janeiro; 
Santa Catarina; Sio Paulo) through Uruguéy (Maldonado) and 
Argentina (Estado del Plata; southern Chaco; Punta Lara; Buenos 
Aires; Ajé; ‘Rancho, breading: Estancia Espartilla, iuseBings Bar- 
racas al Sud; San Martin; Monte) to Chile (Arica Bay); accidental 
on coast of New Jersey (Great Egg Harbor), and on Long Island. 
Sterna trudeaui AupuBoN, Birds Am., fol. ed., iv, 1838, pl. 409, fig. 2 (Great Egg 
Harbor, New Jersey; type now in coll. U.S. Nat. Mus.?); Orn. Biog., v, 1839, 
125; Synopsis, 1839, 319.—Gay, Hist. Chile, i, 1847, 484.—Couss, Proc. Ac. 
Nat. Sci. Phila., 1862, 542 (mongr.); Check List, 1873, no. 571; 2d ed., 1882, 
no. 802; Birds Northwest, 1874, 675.—ScuLtEGEL, Mus. Pays—Bas, vi, no. 24 
(Sternae), 1864, 29 (Brazil) —Lawrence, Ann. Lyc. N. Y., viii, 1867, 299 
(coast New Jersey).—LanpsBrcx, Anal. Univ. Chile, xli, 1872, 515.—Rripe- 
way, Proc. U. 8. Nat. Mus., iii, 1880, 208; Nom. N. Am. Birds, 1881, no. 
684.—Bairp, BREWER, and Riweway, Water Birds N. Am., ii, 1884, 290.— 
AMERICAN OrnITHoLoaists’ Union, Check List, 1886, and 2d ed., 1895, no. 
68; 3rd ed., 1910, p. 44.—DasBeEne, Orn. Argent., 1910, 211 (s. Chaco; 
Estado del Plata). 
@ Saunders, Cat. Birds Brit. Mus., xxv, 1896, 131. 
Notwithstanding that S. trudeauii in its adult plumages is unlike any other species 
in coloration, the immature and young plumages resemble very closely those of S. 
forsteri. The latter may, however, always be distinguished by the darker terminal 
portion to the inner webs of the lateral rectrices, which are relatively narrower and more 
elongated, decidedly shorter hallux, and differently shaped bill, which is more slender 
or at least relatively less deep basally. According to Saunders, the young (which I 
have not seen) of S. trudeauii has the crown and nape paler, with less distinct mottlings. 
6 One specimen. Three other specimens, adults and fully grown immature birds 
of undertermined sex, measure as follows: Wing, 248-276 (256.7); tail, 114-142 (125.8), 
exposed culmen, 39-42 (40.2); tarsus, 22.5-24.5 (23.7); middle toe 19-22 (20.7), 
