Vo1 ' 1920 XYI1 ] Recent Literature. 161 



ever, refers only to the accumulation of former years while the annual 

 production of the birds today amounts to no less than 20,000 tons. The 

 conservation of such an asset is naturally a problem of the utmost import- 

 ance to the government. Indeed this seems to have been recognized from 

 the earliest times for older authors quoted by Mr. Coker tell us that the 

 Inca kings forbade landing on the islands during the nesting season, under 

 pain of death, and the killing of the birds on or off the islands at this time 

 was prohibited. Those who object to the stringency of modern bird and 

 game laws may well take note of this! 



Mr. Coker points out the interesting fact that the value of the guano 

 depends largely upon the nature of the islands selected by the birds as 

 nesting grounds. Those like the Chinchas are absolutely without rainfall, 

 no vegetation is possible and the nitrogen cannot be converted into 

 ammonia and lost by evaporation as would be the case were it subjected to 

 rainfall, but is perfectly preserved in a form readily available for agricul- 

 tural purposes. Some of the more northern islands where rain occasionally 

 falls produce only inferior grades of guano. 



The most important of the guano birds is the White-breasted Cormorant 

 or " Guanay " (Phalacrocorax bougainvillei) and in June 1907, Mr. Coker 

 found their colony on the Chincha Islands covering an area of fifteen acres, 

 while a careful estimate showed that there were some 180,000 nests, and 

 three-quarters of a million birds including old and young. In the following 

 year the colony on these islands was half as large again due in part to acces- 

 sions from another island. The Pelican or " Alcatraz," (Pelecanus thagus), 

 comes second in importance and the Booby, " Piquero," (Sula variegata) 

 third. Von Tschudi placed the Booby first as a guano producer, and his 

 statement has been generally followed ever since, but after careful investi- 

 gation Mr. Coker can find no evidence of conditions having been materially 

 different in Tschudi's time from those prevailing today, and there is no 

 question about the relative rank of the species at the present time. Other 

 birds inhabiting the islands are the Penguin, (JSpheniscus humboldti), 

 several Gulls and Terns, an Albatross (Diomedia irrorata), several Petrels 

 and Shorebirds, an additional species of Booby and two of Cormorants and 

 a Man-o'-war bird. The Condor, two Turkey Vultures and a Passerine 

 bird, the " Chirote," (Cinclodes taczanowskii) complete the list. 



To the life histories of all of these Mr. Coker makes valuable contribu- 

 tions while the economic aspect of the guano industry is exhaustively 

 treated. Twenty-five half-tone reproductions of photographs give one an 

 excellent idea of these remarkable barren islands and the masses of birds 

 which literally cover their surface during the nesting season. Mr. Coker 

 is to be congratulated upon doing an excellent piece of economic work and 

 making at the same time a most important contribution to ornithological 

 literature. — W. S. 



