NO. 2298. THE GUANO BIRDS OF PERU—COKER. 453 



what warmer and more moisture-laden, and it is imdoubtedly true 

 that at rare intervals the northern current has reached at least as far 

 south as the Lobos Islands. Light rains are not unknown at Lobos 

 de Tierra (6.5° south), and this doubtless accounts for the presence 

 of certain very small patches of vegetation and for the inferior 

 quality of the guano. 



With conditions so uniform along the coast, it is evident that at 

 one time or another birds may have occupied rookeries at thousands 

 of different places on mainland or island, and breeding places, even 

 of the distant past, would be marked by the accumulation of guano. 

 Hundreds of places have, in fact, been the seat of commercial opera- 

 tions in the extraction of guano. Chief in historical importance are 

 the Chincha and Ballestas Islands, the islands of Guanape and Macabi, 

 and the larger Lobos Islands, de Afuera and de Tierra. Pabellon de 

 Pica was an important point at one time, but it has passed from the 

 jurisdiction of Peru and was not, therefore, included in the field of 

 my observations. Many places of secondary importance might be 

 mentioned, such as the Islas Santas, Palominos, Fronton, Asia, Santa 

 Rosas, Vieja, and Cerro Azul. 



The writer visited all of the islands of importance except the Islas 

 Santas, northward from Chimbote. A list of these points, with the 

 approximate latitudes, is given in an appendix. There were scarcely 

 any noteworthy breeding places on the mainland at the time of my 

 visit, so that the scenes of observation were principally upon the 

 islands. 



CHARACTER OF THE PERUVIAN ISLANDS.^ 



None of the islands are very large or far removed from the coast. 

 One of the nearest islets (Isla Loberia, near Cerro Azul) is so close to 

 the main shore as to be conveniently reached by an aerial trolley, 

 while most of the islands are not more than 10 or 12 miles removed. 

 The single group at all remote is the Lobos de Afuera, which is about 

 33 nautical miles from the nearest point of mainland. The largest 

 island is that of Lobos de Tierra, with its length of nearly 6 miles and 

 a width varying from one-sixth of a mile to 2 miles. The Lobos de 

 Afuera Islands combined are slightly smaller, while each of the two 

 larger Chincha Islands ^vill not average a half-mile in diameter. The 

 south (and smallest) island of the Chincha group, and recently the 

 most important, has an extent of less than 30 acres, the greater part 

 of which was covered by the nests of birds. The islands of BaUestas, 

 a sister group of the Chinchas, and, like it, composed of three prin- 

 cipal units, are approximately equal to the smallest of the Chinchas. 

 They are bolder and higher and must be gained by climbing from 



» For mention of practically everyisland and detailed description of certain features of thecoast of Peru, 

 see Rosendo Melo's admirable "Derrotero de la Costa del Peru," pp. XLvni, 302. 



