PERU'S WEALTH-PRODUCING BIRDS 



555 



tent, however, and perhaps entirely, 

 the inferiority of recent pelican 

 guano is attributable to climatic con- 

 ditions prevailing on the particular 

 islands where the birds have found 

 safe harbor. 



As far north as the Lobos Islands, 

 atmospheric humidity becomes ap- 

 preciable and, indeed, light showers, 

 though extremely rare, are not un- 

 known. Fresh pelican guano from 

 the Lobos de Afuera Islands gave, 

 by analysis, more than 21 per cent 

 of nitrogen, while random samples of 

 dry guano from the surface of the 

 rookery yielded less than 8V2 P er 

 cent. Comparison of these analyses 

 reveals the deleterious effect of at- 

 mospheric conditions in this locality. 



Comparison of the last analysis 

 with the guanay guano of the Balles- 

 tas Islands, with its 12 to 16 per cent 

 of nitrogen, shows the inferiority of 

 northern pelican guano to southern 

 guanay guano, although this com- 

 parison tells no story of the relative 

 merits of the birds when subjected 

 to the same climatic conditions. 



THE PELICAN YOUNG ARE NAKED AND 

 AND PURPLE-SKINNED 



Regardless of its economic rank, 

 the pelican yields to no other bird of 

 the Peruvian islands in interest to 

 the observer or in the problems it 

 presents for study. 



When one first visits an island in- 

 habited by great numbers of these 

 large birds, the bewildering variety 

 of color phases may well suggest the 

 presence of several species. Longer 

 acquaintance, however, shows that 

 there is but one common Peruvian 

 pelican, which at various ages and 

 seasons displays itself in a diversity of 

 dress. There are patterns corresponding 

 to particular stages, and, since the peri- 

 odic changes of costume take place some- 

 what gradually, there are various com- 

 binations of the several patterns. 



It is interesting, too, to observe the 

 young birds at various stages of growth. 

 Bizarre as an adult pelican may appear 

 alone, it loses by comparison all sugges- 

 tion of grotesqueness when in company 

 with its nestling young. At first naked 

 and purple-skinned, then covered with 



AN OED PEEICAN WHOSE PLUMAGE HAS BE- 

 COME ALMOST COMPLETELY GRAY 



The bill in one species of pelican sometimes 

 measures 18 inches in length. They are strong 

 fliers, their wingspread often reaching ten feet. 

 On the Peruvian coast both the adult birds and the 

 nestlings are beset by parasites, which attach them- 

 selves by scores within the pouches. 



white down, their awkward and uncouth 

 appearance seems for a time only to in- 

 crease with age. 



Attaining a large size before develop- 

 ing their second plumage, they may even 

 exceed their parents in stature and in 

 weight while only slightly feathered. 

 Great down-covered giants they then ap- 

 pear, while still requiring to be fed from 

 mouth to mouth by their parents. The 

 bill, though relatively short and nonde- 

 script in appearance, gives indication of 

 its future style, and the expansive throat 



