356 LIFE-HISTORIES OF BIRDS 



grata, Clisiocampa Americana, Colias philodice^ 

 and many of the Noctuidce, Tortricidcz, and Tineidcz 

 in their larval and perfect stages. 



The Cowbird delights to visit ploughed grounds, 

 where in small flocks it will glean for a long time, 

 unless disturbed. In pasture-grounds where the 

 cattle are grazing, it is a common visitor, nestling 

 among the cattle and sometimes alighting upon 

 their backs and relieving them of their dipterous 

 tormentors which serve it as food; or else search- 

 ing among their droppings for the same. At 

 times it is somewhat rasorial. 



It has no attractions as a singer, and scarcely 

 deserves the name. Its notes are harsh and 

 unmusical. 



The species which seem to be the objects of its 

 special regard in this section, are comprehended 

 within the three families of the Sylvicolidcz, Virco- 

 nidcc, and Fringillidcc. We have detected its eggs 

 within the nests of the following species: . 

 Geothlypis trie has, Dcndrceca <zstiva, Seiurus au- 

 rotapillus, Sctophaga ru tic ilia, Virco olivaceus, V. 

 novcboraccnsis, V. gilvus, Spizella socialis,Melospiza 

 melodia, and Cyauospiza cyanca. There is usually 

 but one egg deposited in the nest, although we 

 have frequently discovered two, and but rarely 

 three. When the egg is laid within the nest of 

 the Summer Yellow Bird, a remarkable degree of 

 sagacity is manifested when there is lacking ability 

 necessary to its removal. To frustrate the design 

 of its author by preventing its hatching, the birds 



