508 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 56. 



(1842 and 1855). It is possible but hardly probable that they were 

 on other islands of the immediate region at that time. It is to be 

 remarked that the south islands, which seems best suited to the 

 guanay, was unoccupied at that time by guano workers, and was, 

 according to his statement, the chief home of the penguin (which is 

 more easily disturbed by intruders than the guanays), and that it was 

 besides abundantly populated with dicing petrels. 



Raimondi's remarks regarding the relative abundance of the several 

 species of birds (except as regards the guanay) may be approxi- 

 mately true to-day. Plotus and Rhyncops, he says, are very rare. 

 Of resident birds ("sedentarias") those which most abounded in the 

 order, in which he named them, were the pelican, the gannet, the 

 gull (L. modestus) the penguin, and the diving petrel. It is evident, 

 then, that these islands were simply preempted by other species, 

 then vastly more abundant than now; accordingly, the guanays 

 found more living room at other places, especially, by Tschudi's 

 account, in regions much further south. In later years the species 

 formerly dominant have, in consequence of the more extensive 

 industrial activities on the islands, either diminished in numbers or 

 been driven to other nesting grounds, making way for the guanay — a 

 species which is less sensitive to disturbance. 



In regard to the guanay, then, it must be concluded either that it 

 has greatly increased in numbers during the past half a century, or 

 else that it has appeared in regions where it was not formerly a 

 regular habitant. The latter is by far the more probable conclusion, 

 for its ancient common name would indicate that it was recognized 

 as the paramount guano bird of prehistoric times, as it is of the present. 



The Sulas, Raimondi stated expressly,^ produce more guano than 

 the pelicans or the cormorants, because, besides inhabiting the rugged 

 places they cover at times a part of the island ("cubren a veces la 

 parte de las islas"). This statement with its qualifying phrase, 

 "at times," scarcely confirms Tschudi, but in the earlier paper ^ he 

 says "the}'' keep themselves in the interior of the island." As these 

 birds in their present abundance find adequate nesting ground upon 

 the cliffs and comparatively abrupt slopes, they now rarely overflow 

 onto the more level ground. This applies not only to the Chinchas, 

 but to the entire coast as observed. We are perhaps justified in 

 assuming that the Sulas have diminished considerably in nmnbers 

 since the period of Tschudi's or that of Raimondi's observations. 



The penguin, SpJieniscus, in Raimondi's time, had quite abandoned 

 the north island, and was rarely found on the middle (these two were 

 being worked), but were in "great abundance" on the south island. 

 These helpless penguins are now in vastly reduced numbers, for, 

 while they are frequently in evidence about the islands of the Chincha 



« Raimondi, A. El Peru. 1902 (1874). « Raimondi, A. Le huano des Isles de Chincha, 1856. 



