546 



THE NATIONAL GEOGRAPHIC MAGAZINE 



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A TYPICAL NESTING PLACE OF PIOUEROS 



The piquero, or Peruvian gannet, is much more pleasing to the 

 eye than the pelicans or the guano-producing cormorants. The adult 

 bird is distinguished by snow-white head, neck, and breast and 

 variegated back. It is swift and graceful in flight. 



and compactness can scarcely be rivaled 

 in any part of the world. Two illus- 

 trations herewith (pages 539 and 542) 

 show small portions of the flock without 

 duplication. Taken together they show 

 considerably less than half of the entire 

 aggregation. 



The nesting ground occupied about 

 two-thirds of the surface of the island, 

 embracing the crown and the gentle 

 slopes of the hill that surmounted its low 

 bluff walls. The nests were very uni- 

 formly spaced, averaging nearly three to 

 the square yard, and not a yard of ground 

 within the outside limits of the rookery 



was unoccupied. In 

 form and arrangement 

 the nests appear as 

 heavy rolled-rim ba- 

 sins stuck into the 

 hillside (see p. 540). 



GUANAYS GRUMBLE AT 

 VISITORS 



When one ap- 

 proaches the rookery 

 the guanays crowd 

 away with much 

 grumbling, and when 

 once a few birds arise 

 in flight the movement 

 i? liable to spread 

 through the entire 

 flock, until hundreds 

 of thousands are on 

 the wing, even most 

 of those that were too 

 remote from the in- 

 truder to know the 

 cause of the disturb- 

 ance. 



If one awaits mo- 

 tionless and with much 

 patience, the birds, 

 after a while, will re- 

 turn to the nests and 

 gradually close in 

 around the observer, 

 until at last only a 

 circle with a radius of 

 three or four feet is 

 left vacant. 



While in every di- 

 rection one is sur- 

 rounded by acres of 

 birds of the same spe- 

 cies, the scene is pe- 

 culiarly variegated. In one direction the 

 birds face toward the intruder watch- 

 fully, and the thousands of snowy breasts 

 make a glistening white ground spotted 

 with black heads. In another direction 

 they are all turned away, and the ground 

 appears almost solidly black ; or a thou- 

 sand birds are seen in side view and the 

 breasts show only as white streaks. 



Other effects are presented, according 

 as the birds are more or less compactly 

 grouped. Near at hand the metallic 

 green reflections from the heads, the 

 green-lustered backs, sides, and legs, the 

 showy white under sides and the hun- 



