468 PROCEEDINGS OF THE NATIONAL MUSEUM. voi.. 56. 



feathers of the shoulders are dark fuscous scarcely tipped with white, 

 and a band of similar feathei^s extends to the breast around the base 

 of the still down-covered neck. The upper surface of the wings is as 

 in the adult, except that the colors, as everywhere on the body, are 

 duller. A conspicuous feature of the immature birds is the cross of 

 white down on the rump which long persists while the rest of the body 

 is becoming fully feathered. The predominant white colors of the 

 adult bird are not evident until a late phase. The young when 

 abandoning the parental nest have practically the entire head, neck, 

 and body a variegated fuscous. At this stage the birds are easily 

 confused with the larger species, Sida nehouxi, unless the measure- 

 ments are considered. 



The young birds go through much home practice in flight before 

 starting away from the nest. They will stand in the nest fla])ping 

 the wings continually for a long time, or, facing the wind and assisted 

 by its power, will rise in the air to remain in an almost fixed position 

 for a considerable time flapping the wings strongly all the while, and 

 then gradually receding to the nest. These practice flights were 

 repeatedly observed, the young birds getting only 3 or 4 feet above 

 the nest and 2 or 3 feet forward, and thus remaining for a minute or 

 more. 



Von Tschudi ^ ascribed to the Sula variegata the chief rank as a 

 guano producer, and his mistake has been frequently followed. 

 There is reason to believe that the habit of this species as regards 

 choice of nesting site has undergone some modification since Tschudi 's 

 time.^ Tschudi was a very careful observer and he spent some 

 years upon the coast, but he expressly states in his Ornithologie 

 (p. 313) that none of the birds nest on the mainland, but only on 

 the barren islands. Such a statement certainly could not be made 

 in the present time. Unless the habits of this bird have materially 

 changed during the past 70 years, Von Tschudi was misled by 

 observation of the evident abundance of the Sulas; and his mistake 

 has been too frequently followed in nearly all reference books. This 

 species now ranks a very poor third in economic importance, being 

 far exceeded by the cormorant and the pelican. Yet this may not 

 be the case in future. As has been previously mentioned, the 

 piquero frequents the rough and scarcely accessible places and even 

 the abrupt cliflFs; and, while practically no place is entirely inac- 

 cessible to the intrepid guano workers, it is evident that from such 

 positions a large proportion of the guano must be lost by falling to 



1 Tschudi, J. J. von. Travels in Peru during the years 1838-1842. Translation by Thomaslna Ross. New 

 York, 1852 (p. 168). Also, 



Tschudi, J. J. von. Untersuchungen iiber die fauna Peruana. 2 vols. St. Gallen, 1844-1840. Vol. 2, 

 Section: "Ornithologie" (p. 313). 



2 Raimondi also believed that Sula variegata produced more guano than pelicans or cormorants, because 

 they keep themselves in the interior of the island (not confirmed by a later statement. See p. 608.) 



