NO. 229S. THE GUAyO BIRDS OF PERU—COKER. 459 



entirely a new-born pelican (with considerable effort) or tear a larger 

 one to pieces, contending with the turkey buzzards over the common 

 prey. The concerted attacks of gaviotas and gallmazos on the nests 

 of piqueros is described in another place (p. 498), 



Besides doing scavenger duty in the rookeries by feeding on dis- 

 carded fish or dead bodies of birds, they were not uncommonly seen 

 perched on the floating body of a peHcan, which had perhaps been 

 killed by a sea-lion, and tearing at the meat, a position undisputed 

 by the gallinazo. I was interested to determine if they were them- 

 selves afraid of the sea-lions. They would always desert a floating 

 body as a sea-lion approached and, though they will rest on the 

 water with the sea-lions nearby, they fly invariably to another position 

 as the "lobo" draws too near. 



The nests were found in December, principally at Lobos de Tierra, 

 but a few were observed at Lobos de Afuera. They were generally on 

 the hills, scattered among the nests of the larger piqueros, and Uned 

 with a few feathers and seaweed (pi. 56, fig. 1). Three nests were found 

 under the shelter of a low bank upon a beach and close to the water. 

 There are almost always three eggs or young, although one nest was 

 found with five eggs. The eggs are olive green, spotted and blotched 

 with dark brown (75 by 50 mm.). The very small birds have a 

 black bill with light tip, and are covered with thick soft down, gray 

 in ground color but brmdled with fuscous; the head is distinctly 

 spotted with dark fuscous on a light gray background. When quite 

 young they will run about, leaving the nest to hide among the rocks 

 as an intruder approaches. 



The gaviotas have a variety of color phases with the age and 

 season. The head, at one stage dark gray or nearly black, becomes 

 white-mottled and then pure white; the black tail with white base 

 and tips becomes a white tail with narrow black bar. 



The nests of the gaviotas are practically devoid of guano, so that 

 their economic significance depends principally upon their service as 

 scavengei-s and, on the other hand, their depredations upon other 

 birds. 



STERNA HIRUNDINACEA (Lesson). 



THE TERRECLE. 



Among the terns, particular attention was given only to the 

 " terrecle, "Sterna hirundinacea {Liesson),^ and the "zarciUo, "Larostema 

 inca (Lesson). 



The terrecle is very common in the southern region particularly. 

 The principal breeding places observed were San Gallan (Jmie 25) 

 and the Islas de Santa Rosa at the Bay of Independencia (July 18, 



> The bill was deep blood red and the tarsus a brighter red, in the specimens of S. hirundinacea collected, 

 although Taczanowsla describes the parts as yellow and yellowish. The outer third of the upper bill of 

 one specimen was almost black. 



