THE COWBIRDS. 



603 



Tbe Cowbirds are sociable to a greater degree than most species, 

 their companies not breaking up during tbe laying season ; for, as they 

 are parasitical, the female merely steals away to drop her egg in any 

 nest she can find, after which she returns to the Hock. They feed on 

 the ground, where, in their movements and in the habit the male basin 

 craning out its neck when disturbed, they resemble Starlings. The 

 male has also a curious habit of carrying his tail raised vertically 

 while feeding. They follow the domestic cattle about the pastures, and 

 frequently a dozen or more birds may be seen perched along the back 

 of a cow or horse. When the animal is grazing they group themselves 

 close to its mouth like chickens round a hen when she scratches up the 

 ground, eager to snatch up the small insects exposed where the grass 

 is cropped close. In spring they also follow the plow to pick up worms 

 and grubs. 



The song of the male, particularly when making love, is accompanied 

 with gestures and actions somewhat like those of the domestic pigeon. 

 He swells himself out, beating the ground with his wings, and uttering 

 a series of deep internal notes, followed by others loud and clear; and 

 occasionally when uttering them he suddenly takes wing and Hies 

 directly away from the female to a distance of 50 yards, and performs 

 a wide circuit about her in the air, singing all the time. 



The homely object of his short-lived passion always appears utterly 

 indifferent to this curious and pretty performance; yet she must be even 

 more impressionable than most female birds, since she continues scat- 

 tering about her parasitical and often wasted eggs during four months 

 in every year. Her language consists of a long note with a splutter- 

 ing sound, to express alarm or curiosity, and she occasionally chatters 

 in a low tone as if trying to sing. In the evening when the birds con- 

 gregate on the trees to roost they often continue singing in concert 

 until it is quite dark; and when disturbed at night the females fre- 

 quently utter their song while taking flight, reminding one of the 

 Icterns pyrrhoptcriis, which has only its usual melody to express fear 

 and other painful emotions. On rainy days, when they are driven to 

 the shelter of trees, they will often sing together for hours without 

 intermission, the blending of innumerable voices producing a rushing 

 sound as of a high wind. At the end of summer they congregate in 

 flocks of tens of thousands so that the ground where they are feeding 

 seems carpeted Avith black, and the trees when they alight appear to 

 have a black foliage. At such times one wonders that many small 

 species on which they are parasites do not become extinct by means of 

 their pernicious habit. In Buenos Ayres, where they are most numer- 

 ous, they have a migration, which is only partial, however. It is notice- 

 able chiefly in the autumn, and varies greatly in different years. In 

 some seasons it is very marked, when for many days in February and 

 March the birds are seen traveling northward, flocks succeeding flocks 

 all day long, passing by with a swift, low, undulating flight, their wings 



