NO. 2298. 



THE GUANO BIRDS OF PERU—COKER. 



493 



given adequate consideration in connection with the protection of 

 birds. As previously indicated, ideal conditions prevail in the region 

 of the Chincha Islands, but not to a like extent in the north. Rain, 

 indeed, is very rare on the Lobos Islands,^ but the humidity there is 

 much higher, so that a considerable proportion of the nitrogen of the 

 guano escapes in the form of ammonia. Consequently no Lobos 

 Island guano is of the high quality of the Chincha guano, and this 

 difference is not due solely to the difference of the species of birds 

 acting as chief producers. As a matter of fact, the freshly made 

 guano of the pelican may be very high in nitrogen. Analysis of 

 pehcan guano, taken from a cage in which I kept a pelican, and 

 bottled the same day as deposited (but after allowing to dry), showed 

 a nitrogen content of 21.66, with phosphoric acid in amount 4.30; 

 while a sample taken from the surface of the rookery on the same 

 island (Lobos de Afuera) analyzed only 8.41 nitrogen and 17.40 phos- 

 phoric acid. Comparison of guano cake from the rookery of guanays 

 in the Chincha region shows 15.91 per cent of nitrogen and 8.89 per 

 cent phosphoric acid.^ Of course it is primarily the nitrogen that 

 determines the value of this fertilizer. The difference in percentages 

 of nitrogen in the cage and rookery guanos is not to be attributed 

 solely to atmospheric conditions, but is accounted for partly by the 

 foreign materials which pelicans introduce on the nesting grounds in 

 much greater degree than do the guanays, all of which add to the 

 bulk with less proportionate addition to the value of the guano. The 

 complete analyses show, however, that the fresh unmixed peUcan 

 guano and the guanay rookery guano (Ballestas Islands) have nitrogen 

 constituting more than a fourth of the organic matter (26 and 28 per 

 cent, respectively), while the guano from the pelican rookery (Lobos 

 de Afuera) shows nitrogen as less than one-fifth of the organic matter 

 (19 per cent). 



I That rain has occurred on the Lobos de Tierra Islands was evidenced by the signs of comparatively 

 recent erosion. Some very distinct, though small, water channels wore noticed on some of the hills. I 

 was told by the fishermen that a light rain had fallen two years previously. 



» The complete analyses are as follows: 



Moisture 



Sand 



Organic matter (a) • 



Phosphoric acid (b) • 



Alkalies, etc 



(a) Containing nitrogen • 



Equal to ammonia 



(b) Equal to tricalcic phosphate 



Analyses by Mr. H. H. Bunting, F. C. S., of Callao. 



Pure guano 

 of pelicans 

 from cage. 



9.40 



.85 



81.75 



4.30 



3.70 



100.00 

 21.66 

 26.30 

 9.38 



Guano of 

 pehcans 



from 

 rookery, 

 Lobos de 

 Afuera. 



16.14 

 9.10 



43.86 

 17.40 

 13.50 



100.00 

 8.41 

 10.21 

 37.98 



Guano of 

 guanay 



from 

 rookery, 

 Ballestas 

 Islands. 



20.26 



.75 



56. 59 



8.89 



13.51 



100.00 

 15.91 

 19.32 

 19,41 



