464 U. S. NATIONAL MUSEUM BULLETIN 211 



at times in fields of ripening grain or rice might be less creditable, but of this we 

 know nothing as yet. 



The Red-eye associates considerably with cattle and in all probability does so 

 for the insects it finds scared up by the grazing animals, but my stomach content 

 examinations have failed to reveal even a trace of insect food. 



In southern Vera Cruz these cowbirds evidently do considerable 

 damage to grain crops, for Alexander Wetmore (1943) says: 



Red-eyed cowbirds were found in small flocks, regularly at the village, and also 

 around the lagoons. As the corn matured they spread out through the fields to 

 feed on the grain in company with Cassidix, and at times I saw them in such lo- 

 calities in flocks. When the ears were ripened the natives went into the fields to 

 bend or break the stalks at an abrupt angle below the ears, so that these instead of 

 standing upright were turned down toward the ground and were covered by the 

 stalks above. Whole fields treated in this way presented a curious appearance. 

 The theory was that the ears were thus hidden so that they were protected from 

 damage by birds. Before this, while grain was in the milky stage, men and boys 

 went out at dawn to the fields armed with slings and slingshots, or with clods to be 

 thrown by hand. They stood on small elevated platforms of poles that gave them 

 clear view across the corn, where by shouting or by casting missiles they kept the 

 birds moving and so prevented damage. 



Alexander F. Skutch contributes this account of the feeding habits: 

 "True cow-pen buds, the red-eyed cowbirds often forage close beside 

 the heads of grazing cattle, snatching up the insects which the animals 

 stir up from their lurking places amid the herbage. They also alight 

 upon the backs of horned cattle and mules to vary their diet with 

 ticks and insect pests which they pluck from the animals' skin. Often 

 they forage in the pastures in company with the far bigger giant cow- 

 birds (Psomocolax oryzivorus) and groove-billed anis. 



"The red-eyed cowbirds also joined the giant cowbirds and other 

 members of the Icteridae in another and most unexpected form of 

 hunting. Along the Rio Morjd, a small tributary of the Rio Motagua 

 in Guatemala, was a broad, bare flood plain, covered with small, 

 water-worn stones, where I could count upon watching the cowbirds 

 feed almost every evening, from an hour or so before sunset until the 

 sun had sunk behind the cane brakes. The giant cowbirds formed the 

 nucleus of these assemblages, but their party was joined by red-eyed 

 cowbirds, a few great-tailed grackles (especially the males) , and Sumi- 

 chrast's blackbirds (Dives dives). Often a few wild Muscovy ducks 

 would forage near these smaller buds in the shallows; at a little dis- 

 tance, all five species appeared sufficiently black to remind me of the 

 truth of the old adage 'Buds of a feather flock together'. For some 

 reason, the male giant cowbirds resented the presence of the male red- 

 eyed cowbirds and often pursued them, although they never drove 

 them far away. 



The chief occupation of both kinds of cowbirds was stone-turning, 

 for which their strong, black bills seemed well fitted. They moved 



