THE COWBIKDS. 



595 



HelmintlwpMln jriniis, Blue-winged War- 

 bler. 



Helminthophila chry.sopfera, Goldeu- 

 wiuged Warbler. 



HehninthopMla riificainlla, Nashville 

 Warbler. 



Compsothlypis americana, Parula Warbler. 



Dendroica a'sth-a, Yellow Warbler. 



Dendroica cwrulescena, Black-throated 

 Bine Warbler. 



Dendroica cirrulea, Cerulean Warbler. 



Dendroica hiackhurnia;, Blackburuian 

 Warbler. 



Dendroica virens, Black-throated Green 

 Warbler. 



Dendroica discolor, Prairie Warbler. 



Seiiirus aurocapilhis, Ovenbird. 



Seiurus noveioracensis, W\ater Thrush. 



Seinrns rn()toci/?a,LonisianaWater Thrush 



GeoMypis formosa, Kentucky Warbler. 



Geothylpis irichas, Maryland Yellow- 

 throat. 



Geothylpis irichas occidentalis, AVestern 



Yellow-throat. 

 Icteria virens. Yellow-breasted Chat. 

 Icteria virens longicanda, I^ono-tailed 



Chat. 

 Sylvania mitrata, Hooded Warbler. 

 Setophaga ruticilla, American Redstart. 

 Galeoscoptes carolinensis, Catbird. 

 Harporhynchus rufns, Brown Thrasher. 

 Salpinctes ohsoletus, Kock Wren. 

 Troglodytes a-don, House Wren. 

 rarm hicolor, Tufted Titmouse. 

 Polioptila cmrulea, Blue-gray Gnat- 

 catcher. 

 Turdus musielinus, Wood Thrush. 

 Turdusfiiscescens, Wilson's Thrush. 

 Ti(rdi(s ustiilatus swainsonii, Olive-backed 



Thrush. 

 Tardus aonaJaschlae aiiduboni,Auduho\i's 



Hermit Thrush. 

 Merula miqraioria, American Robin. 

 Sialia sialis. Bluebird. 



Among these the nests of the Phoebe, Soug Sparrow, To whee, Indigo 

 Bnnting, Ovenbird, and Yellow-breasted Chat seem to be most 

 frequently selected, and these usually contain also more of the para- 

 sitic eggs than the majority of the others. 



The egg of the Cowbird usually hatches in from ten to eleven days, 

 generally^'in advance of those of the foster parent, and the growth of 

 the young interloper is rapid. Mr. M. A. White, of Mathews, Va., 

 writes on this subject as follows, and his observations correspond fairly 

 well with my own : 



It was on the 9th of June, 1891, that I placed a fresh egg of the Cowbird in the nest 

 of a Chipping Sparrow containing two of her own that had an advance of one and 

 a half days' incubation over the first. I watched results. About the 19th, Mr. Cow- 

 bird emerged from his prison walls, large and vigorous. A day later a little sparrow 

 came forth from his delicate shell, but much smaller, and exhibiting less strength 

 than his fosterbrother. The other egg failed to hatch. 



The daily increase in dimension of the Cowbird was something immense, while 

 that of hisVounger companion seemed rather to diminish than enlarge, until finally, 

 at the end of three days, he died-evidently for want of food, as the Cowbird, being 

 laro-er greedily devoured everything that came in contact with his capacious mouth. 

 The untimely end of the rightful heir was but gain to this usurper, as he now 

 received the whole attention of the parent birds. Nature having now, at the early 

 ao-e of seven days, provided him with a respectable dress, he was no longer con- 

 tented to remain within the small compass which the nest furnished, whereupon he 

 betook himself to the branches of the tree in which the nest had been placed. But 

 soon this area became too limited for his ambitious spirit, for at the end of his 

 second week he was flitting from bush to bush, exploring the fields anfl hedges, his 

 foster parents providing for him all the while. Two weeks more and he was a fuU- 

 fled«'ed bird. About July 20 I saw him for the last time.* 



* The Oologist, Vol. X, Aug., 1893, pp. 230, 23L 



