478 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 56. 



may be suggestive of the sullen mutterings of a disgruntled mob 

 of human beings.^ 



When the guanays leave the island in search of food they appear 

 as a long black cloud several miles in length, streaming low over the 

 water until they settle down to form a large black blotch on the 

 urf ace of the sea. As a flock in flight rises on approaching an island 

 it may be seen that the birds do not form an indeterminate mass, but 

 are distributed in lines that bend and sway, ascending, descending, 

 or swerving from side to side. The position of these varying curves 

 at any moment could be reproduced by a drawing or a photograph; 

 but the pleasing effect of the wave-like movement of the lines inter- 

 secting each other at ever-varying angles is impossible of representa- 

 tion. 



The guanays are afflicted with parasites, but to a far less extent 

 than the pelicans. One of the parasitic insects is said to inflict a very 

 pernicious bite on human beings. 



The economic importance of the guanay will be discussed after 

 treating the other species of cormorants of the Peruvian coast, (See 

 p. 482.) 



PHALACROCORAX VIGUA (Vieillot). 



THE BLACK CORMORANT OR "CUERVO DE MAR." 



The "cuervo de mar" ("sea crow") is the common cormorant of 

 the docks and piers of the coast as well as of the inland v/aters. They 

 are rarely seen in long flight, but are almost invariably observed close 

 to the shore swimming on the water or diving from low perches. 

 They are generally in comparatively small groups, not exceeding a 

 few hundreds in number. 



In appearance this is the least attractive of the cormorants. Its 

 general color above and below is dark brown, the back and belly 

 showing some dark green. The naked parts are dusky black, except 

 for the yellowish skin at base of jaws and chin. The large pouch- 

 like throat enables them to swallow comparatively large fish, but 

 gives them a coarse appearance. A long crest on the lower half or two- 

 thirds of the neck can be raised like the bristles on a hog's back. The 

 voice is a hoarse grunt. Walking over the long pier at Pisco for the 

 first time persons not infrequently suppose that pigs are in some way 

 penned below the pier, being misled by the grunts of hundreds of 

 cormorants resting on the iron tie-rods and braces below. 



The Cuervos dwell little on the islands. At the Chinchas and Bal- 

 lestas opposite Pisco, a few are commonly seen perched in line on the 



> These notes regarding the voice of the guanays, individually or collectively, are transcribed verbatim 

 from my field notes made in 1907. Forbes (1913) derived a strikingly similar impression. He says: "At 

 times the noise is just like the sough of the sea and at others it resembles the sound of a great crowd, all the 

 members of which are talking at once." Additional notes of interest regarding this cormorant are com- 

 prised in his paper, cited as follows: [Forbes, H. O.] The Peruvian guano islands. The Ibis, ser. 10, 

 vol. 1, Oct. 6, 1913, pp. 709-712. (Under "Notes and Discussion.") 



