454 PROCEEDINGS OF THE NATIONAL MUSEUM. voi.. 56. 



the water, being without beaches except at the bases of unscalable 

 cliffs. These islands of Ballestas are from 100 to 300 feet in height. 



All of the islands are more or less bold, rocky, and barren. The 

 rocky nature of the ground and the general presence of too strongly 

 concentrated fertilizer, as well as the want of atmospheric moisture, 

 would seem to preclude the possibility of plant growth. At any rate, 

 vegetation of any kind is entirely absent, except where the higher 

 points reach such an altitude (about 1,200 feet) as to derive moisture 

 from the clouds; the higher peaks may, therefore, support luxuriant 

 but entirely isolated gardens of vegetation. This occurs only on such 

 lofty islands as San GaUan, La Isla Vieja, and San Lorenzo. 



Naturally, on such barren islands, when the ultimate source of 

 food is in the sea, the fauna is very restricted. Besides the birds and 

 sea-lions, we find only parasitic insects, and their enemies, the spiders, 

 scorpions, lizards, and bats; ^ except that, on the verdure-clad peaks 

 just mentioned, colonies of land snails have in some v.'ay been intro- 

 duced, perhaps by the condors which visit back and forth from main- 

 land to island. Escaped cats live freely on Lobos de Afuera. I 

 observed an otter in the water near the beach of San Gallan, and 

 also captured a specimen of cricket on the beach of the same island.' 



There are certain islands for which the birds show a predilection, 

 and some of these appear to have been favored breeding places for 

 centuries. Particular islands appeal to the fancy of certain birds, so 

 that for each island or group of islands there may be a particular bird 

 claiming "eminent domain." As instances, there may be cited the 

 possession of the South Chincha and the Ballestas Islands by the 

 white-breast cormorant, San Gallan by a diving petrel, one of the 

 Santa Rosas Islands by the little tern (S. Jiinindinacea) and the 

 Lobos Islands by the pelican, and the larger gannet. Off-lying islets 

 may be taken by another species than the one occurring in principal 

 abundance on the main island. Thus, in the realm of the corm.orants 

 at the Chinchas, a small rookery of pelicans occupied the flat top of 

 an islet near the north island; while just across from the pelican 

 rookery on Lobos de Tierra, a low islet was crowned with cormorants. 



Briefly to indicate the economic significance of the guano birds, it 

 may be recalled that a quantity of more than 10,000,000 tons of 

 high grade guano is reported to have been extracted from the Chincha 

 Islands between 1851 and 1872. Such an amount of guano of the 

 high grades then exclusively used would have a pre-war value of 



> Examples of lizards and bats collected by the writer on the guano islands and deposited in the United 

 States National Museum were identified as follows: Phyllodactylus genhopygus (Wiegmann), lizard from 

 Ban Gallan Island, near the beach. Phyllodactylus inegualis Cope, lizard from Lobos de Afuera Island, 

 near the beach. Tropidurus peruvianus (Lesson), lizards from Lobos de Tierra, near the beach, and from 

 Chincha North Island. Desmodus rotundus rotundus (Geoffrey), bat from cavern in one of the Ballestas 

 Islands. 



2 The description of the islands is taken in part from an unpublished manuscript of the writer, which is 

 in the hands of the National Geographic Society. 



