Paraguay , Bolivia , and Southern Brazil. 
473 
including the 1st of March several of these Terns were seen, 
sometimes singly and sometimes in pairs, passing along the 
Atlantic coast, but generally very far out at sea. I had not 
met with this species in the Ajo district before. It has a 
very clear shrill cry, which cannot be mistaken. 
266. Sterna trudeauii. 
Sterna trudeauii Arg. Orn. ii. p. 195; Saunders, Cat. B. 
xxv. p. 130. 
a, h. c? £ ad. Los Ynglases, Ajo. Oct. 27, 1908. 
c. S ad. 
d. $ imm. 
e. <$ imm. 
f. g. ? imm. 
Nov. 1, 1908 
Feb. 2, 1909. 
Feb. 21, 1909. 
Mar. 1, 1910. 
Trudeau’s Tern is, I think, the only resident Tern in the 
Ajo district, where it is quite plentiful, especially on the coast, 
and flocks of many hundreds can be seen any day. The 
flight is low and graceful, and the cry a sort of “ whew.” 
It is also met with on every lagoon and open sheet of water 
inland. 
267. Sterna superciliaris. 
Sterna superciliaris Saunders, Cat. B. xxv. p. 121. 
a. S a( i. Riacho Ancho, N. Argentine. Aug. 1, 1909. 
b. S ad. Desaguadero, Paraguay. Aug. 29, 1909. 
c. S ad. Colonia Risso, ,, Sept. 9, 1909. 
d. cJ nestling. Colonia Risso, Paraguay. Sept. 9, 1909. 
e. S y°ung. Near Puerto Braga, „ Sept. 24, 1909. 
/. $ young. Colonia Risso, ,, Oct. 26, 1909. 
The adults are in breeding-plumage; that shot on the 
29tli of August has still a few white feathers on the head, 
and new black feathers are replacing them. 
This little Tern was fairly plentiful throughout the river 
trip, and was found breeding, as described under Phaethusa 
magnirostris. As I stated there, it leaves the colony on being 
disturbed, and I only secured one specimen on Sept. 9th, 
when we were some time ashore. One or two returned, but 
flew very high and almost out of shot. 
