482 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.56. 



gaimardi, refers, I take it, to its small size among tlie cormorants. 

 This cormorant has no appreciable economic value. 



The three species of cormorants above described offer a striking 

 illustration of the adaptability of nature. Three birds closely 

 related, withhi the same genus in fact, dwelling in the same localities 

 and not differing greatly in size, afford such striking contrasts in 

 habits and appearance, as may be expressed in the following analysis. 



Social hahit.— The one herds in enormous flocks, another forms 

 small groups, while the third is never seen except singly or in pairs. 

 Of the two extremes, the patillo is always thought of as an individual, 

 even though chance might bring several birds together, but the indi- 

 viduality of the guanay is always lost in the multitude. 



Breeding hahit. — The one nests crudely on the broad expanses of 

 the island tops, another on the rough outljdng rocks, while the third 

 finds isolated homes on the cliffs or in the caverns v/here it constructs 

 strong and secure nests of variously collected materials. 



Feeding hahit. — The one flies out in great flocks to swim on the 

 surface and dive for prey in the schools of surface fishes; another 

 watches from its low perches or dives down to capture the fishes of 

 the bottoms near shore; while the third often makes long single 

 flights before diving in search of eels or other fish or for nest-building 

 materials. 



Voice. — The one utters a distinctive croak, the second makes a 

 harsh gutteral grunt, whfle the third has a high-pitched voice of the 

 timbre of a song bird. 



Color. — The guanay has a shiny black back and glossy white 

 breast, the cuer\^o is dark and of almost uniform coloring, and the 

 patillo is of generally variegated coloi with white stripes and scarlet 

 feet. 



The patillo (P. gaimardi) is lather remarkable among cormorants 

 for the entire absence of any disposition to gregariousness, and it is 

 the most specialized of the tlu-ee in its vrell-developed habit of nest 

 construction and its instinct of protection of young, shown in the 

 choice of location for the home. 



All of the Peruvian cormorants are smaller than the American 

 carho, but the guanay and the cuervo are about equal in size to the 

 double-crested cormorant, the patillo being much smaller. The long 

 bill of the guanay nearly equals that of Phalacrocorax carho. 



Specimens of the "patillo" weighed 2 7/8 to 3 1/8 pounds. The 

 "cuervo" weighs 3 1/8 to 3 1/4 pounds, while the guanay has a weight 

 of 41/2 pounds. 



ECONOMIC IMPORTANCE OF THE CORMORANT. 



The guanay (Phalacrocorax hougainvillei) is the only one of the 

 cormorants having especial economic value, but this one outranks 

 aU the other birds of the coast in significance as a guano producer. 



