412 DIVISION I. VERTEBRAL ANIMALS. — CLASS II. AVES. 



BeloiV'iiig to tills group is the American Cow BirJ, or Cow Troopial, as 

 it is sometimes called. This speeies, like the Eiiropciin Cuckoo, prcpurcs 

 no nest, hut selects those of other birds, distributing one or two eggs to 

 each, and leaving them to be hatched, and the nestling to be reared, by foster- 

 parents. 



The birds whose nests it chiefly selects are the red-eyed and \\ hite-eycd 

 vireos, and the INIaryland yellow throat ; but the bluebird, the indigo bird, 

 the cliiii[)ing sjjurrow, the yellow warbler, the golden-crowned thrush, and 

 many others, are also thus imposed upon. Says Xuttall, — 



" When the female is dis[)osed to lay, she appears restless and dejected, 

 and separates from the unregarding flock. Stealing through woods and thick- 

 ets, she pries into tiie bushes and brambles for the nest that suits her, into 

 which she darts in the absence of its owner, and in a few minutes is seen 

 to rise on the wing, cheerful and relieved from the an.xiety that oppressed 

 her, and [irocecds back to the flock she had so recently forsaken. If the 

 egg be dc[)osited in the nest alone, it is uniforndy forsaken ; but if the nurs- 

 ing ])arent have any of her own, she inunediately begins to sit." 



]\Ir. Xuttall knew of the red-eyed ^'ireo beginning her incubation with only 

 an egg of each kind, whilst in other nests he noticed as many as three 

 belonging to the \'ireo and one to the Cow Bird. 



AVe have found nests of the Yellow A\'arbler with two Cow Bunting's 

 (.frgs in them, and we have in our possession several nests of this species in 

 which the Troojiial, having laid an egg, the AVarblers, in order to prevent 

 the hatching of the parasite, built upon the nest another structure (com- 

 pletely covering the Cow Uird's egg), in which the righlfid nestlings were 

 hatched and reared, the Troojiial's egg remaining covered up until it was 

 ad<lled. The Cow Bird's egg, being larger than those with which it is 

 deposited, receives a larger share of the heat of the iui-uljating bird, and is 

 hatched generally a day, or perhaps more, before the others. The young 

 stranger, being larger than its companions, often stifles them by its su[)erior 

 Weight, when they arc conveyed to a distance by the parent and dropped : 

 they are never, or at least very rarely, found below the nest, as they woidd 

 be if they were ejected by the young Cow Bird, which shows that it has no 

 hiistile feelings against its foster-companions. " Indeed," says Mr. Xuttall, 

 " as far as I have had opportunity of observing, the foundling shows nn hos- 

 tility to the natural brood of his mn-ses, but he nearly absorbs their whole 

 attention, and early displays his characteristic cunning and self-possession. 

 "When fidly fledged, they quickly desert their foster-parent, anil skidk about 

 in the woods, luitil at length they instini.'tively join company with those of 

 the same feather ; and now, becoming more bold, are seen in parties of five 

 or six, in the fields and lanes, gleaning their accustomed subsistence." 



