NO. 2298. THE GUANO BIRDS OF PERU—COKER. 503 



its big bill. The defense was quite useless. It was carried below 

 the surface, and when it appeared again its helpless condition and 

 the blood in the water showed that the fight was finished. The lobo 

 was tearing off the meat from the belly and the water about was red. 

 Ho continued tearing his prey until our boat could arrive and take 

 the mutilated body. This was subsequently photographed. The skin 

 and feathers of the whole lower part of the body, with the meat, some 

 of the bone, and the entrails, had been torn away. As the lobo was 

 still tearing at the alcatraz when it was taken, it is evident that the 

 meat of the bird, and not simply the fish within, was the object of 

 the attack. On another occasion I found floating in the water a bird 

 mutilated in similar fashion. It was evident, however, that -these 

 cases were so rare that, so far as the birds were concerned, no serious 

 destructive effect could be charged to the sea lions. 



Reference has been made previously to the evident fear of large 

 animals, such as porpoises and sharks, manifested by a tamed peUcan. 



THE ALLEGED COMMENSAL RELATION OF SEA LIONS AND BIRDS. 



It is undoubtedly an advantage to the birds that larger animals 

 demoralize the schools of small fish and keep them at the surface. 

 Yet I was not able to see the same close relation in this way, between 

 useful birds and sea lions, as between birds and bonitoes. Fre- 

 quently, there have been opportunities to observe a school of ancho- 

 betas pursued by bonitoes below and birds above. As one watches 

 such as assembly of fishes and birds appear from the distance on the 

 one side, pass and disappear again on the other, the thousands of 

 small fish breaking the surface as the bonitoes leap among them and 

 the cloud of birds plunging and diving, one is left with little doubt 

 as to the benefit that the guano-producing birds may derive from the 

 bonitoes. In regard to sea lions, porpoises, and sharks, this relation 

 is not so clear. The small birds which pick their food from the sur- 

 face without necessarily going into the water, such as the terns and 

 sea gulls, may frequently be seen hovering over and following the sea 

 lions for advantage in capturing small fish. There is no doubt as to 

 the benefit they derive, although such fowl are not valued from the 

 economic side. The chief birds, the "guanay" and the pelican, as 

 well as the gannet, take their fish by going into the water, and it is 

 probable that fear of the sea lions and other large animals would deter 

 these forms from dropping into the sea close about such animals. For 

 several minutes I have watched pelicans and gannets circle over a 

 school of anchobetas without a plunge, until I supposed that the 

 birds could not be hungry, for the fish were breaking the surface in a 

 dozen places and were easy of access; then suddenly they began to 

 make their headlong plunges from the air. It is difficult to apply 

 any other explanation for the delay than that a preliminary recon- 



