484 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 00. 



One may easily appreciate what enormous value such flocks of 

 birds may have. A single ounce of permanent guano for each bird 

 deposited each day, with a flock averaging 500,000 birds, would rep- 

 resent 15^ tons of guano a day, or 5,700 tons a year. During the 

 period of my stay in Peru the south island of the Chinchas was kept 

 permanently "closed." No guano extraction was allowed by the 

 Goverimient, and the birds were undisturbed; this island was visited 

 after one, and again after two years of closure. On the occasion of 

 the latter visit it was estimated that between 12,000 and 15,000 tons 

 had accumulated, and it was confidently predicted that at the ex- 

 piration of the third year the recent deposit would amount to not less 

 than 20,000 tons. These estimates were based on measurements of 

 the thickness and the area of the deposits. Twenty-six measurements 

 of thickness after 20 months closure showed an average depth of 18.5 

 cm., or 7.4 inches, indicating an annual deposit of 11.1 cm., or 4^ 

 inches, the weight of which would be about 300 pounds a square 

 meter. Meantime, however, owing to the fortunate protection ex- 

 tended the birds by the enforced closure, the flock seemed to gain 

 steadily in size. After closure for three years and four months, from 

 November, 1906, to March 1, 1910, the island was reopened, and the 

 published report ^ shows that 23,512 toneladas were taken from that 

 island by the Compania Administradora del Guano (22,337 English 

 short tons, or 21,631 metric tons). 



Guano of this high grade in nitrogen content rarely reaches the 

 United States. For purposes of appraisal, however, it may be said 

 that such guano, if purchased on the islands at $40 a ton, brought to 

 the United States, and sold at prewar prices, would have yielded a 

 substantial profit after defraying aU expenses. Consequently the 

 value of the guano deposited by this single flock during a period of 

 a little more than three years may be stated at nearly $1,000,000. 

 To quote from a previous report of mine:^ 



From the various calculationa I have made it appears that a rookery will yield 

 about 1 long ton of guano per year for 28 nests. Twenty-eight nests or 28 pairs of birds 

 have an annual producing value of $40 net. We give a fair idea of the commercial 

 significance of these birds to Peru when we say that each brace of birds contributes 

 annually $1.43 worth of guano, besides leaving a pair of offspring to continue its 

 service. Is it not, then, of the greatest importance that the fullest protection should 

 be extended the birds, and every possible precaution taken to insure that there may 

 be the maximiun number of birds at every rookery, and that these birds may remain 

 upon the rookery the maximum amount of time? [Page 359.] 



Fowl which produce $1.43 worth of guano a pair annually, without 

 expense for care and feeding except the minimal cost of protection, 

 may well be appraised at $15 a pair. The fowl which dwelt on the 

 South Chinoha Island alone, when it was visited in 1907, might well 



> Compaftia Administradora del Guano, Limitada. La memoria del directoria. Lima, 1910. [p. 21.1 

 s The flshenes and the guano industry of Peru. Bulletin of the Bureau of P'isheries for 1908, vol. 28. 

 1910. pp. 333-365. 



