(GREAT-BILLED TERN.)
+Sterna magnirostris+, _Burm. La-Plata Reise_, ii. p. 519 (Rio
Paraná); _Saunders, P. Z. S._ 1876, p. 643; _Barrows, Auk_, 1884,
p. 316 (Entrerios). +Phaëthusa magnirostris+, _Scl. et Salv.
Nomencl._ p. 147; _iid. P. Z. S._ 1871, p. 567; _Durnford, Ibis_,
1877, p. 200 (Buenos Ayres).
_Description._--Crown, ear-coverts, and nape black; mantle
slate-grey, passing into white at the tips of the secondaries;
wing-coverts white; quills black; tail slate-grey; lores and entire
underparts glossy white; bill yellow, with a greenish tinge at the
base of under mandible; legs and feet olive-yellow: whole length
14·5 inches, wing 11·5. In the young the crown is grey; the mantle
browner grey.
_Hab._ Coasts and rivers of South America.
This large-billed Tern, "with a slightly forked tail, but amply
developed feet," is occasionally seen near Buenos Ayres.
Durnford tells us that he found it common at Baradero in April in small
parties, and watched one flock for some time. These individuals kept
circling over a mill-pond, which evidently held a good supply of small
fishes; for they constantly kept darting into the water. This species,
Durnford adds, has a note quite unlike that of any other Tern; it is
nearly similar to the cry of the "Tero-tero" (_Vanellus cayennensis_),
for which he had often mistaken it.