182 OMNIVOROUS BIRDS, 



Mr. C. Pickering, found two nests of the Blue-eyed Yel- 

 low-warbler, in which had been deposited an egg of the 

 Cow-bird previously to any of their own ; and unable to 

 eject it, they had buried it in the bottom of the nest and 

 built over it au additional story! I also saw, in the 

 summer of 1830, a similar circumstance with the same 

 bird, in which the Cow-bird's egg, though incarcerat- 

 ed, was still visible on the upper edge, but could never 

 have been hatched. At times, I think it probable, that 

 they lay in the nests of larger birds, who throw out the 

 Ggg, oi* that they drop their eggs on the ground without 

 obtaining a deposit, as I have found an egg of this kind 

 thus exposed and broken. I have also remarked some- 

 times 2 of these eggs in the same nest, but in this case 

 one of them commonly proves abortive. 



The most usual nurse of this bird appears to be 

 the Red-eyed Vireo, who commences sitting as soon as 

 the Cow-bird's egg is deposited. On these occasions, I 

 have known the Vireo to begin her incubation with only 

 an egg of each kind, and in other nests I have observed 

 as many as 3 of her own, with that of the intruder. From 

 the largeness of the strange egg, probably the nest im- 

 mediately feels filled, so as to induce the nurse directly to 

 sit. This larger egg, brought nearer to the body than 

 her own, is consequently better warmed and sooner hatch- 

 ed ; and the young of the Cow-bird, I believe, appears 

 about the I2th or 13th day of sitting. The foundling is 

 very faithfully nursed by the affectionate Vireo, along 

 with her own brood, who make their appearance about a 

 day later than the Troopial. From the great size of the 

 parasite, the legitimate young are often stifled, and, when 

 dead, are conveyed, as usual, by the duped parent to a dis- 

 tance before being dropped ; but they are never found im- 

 mediately beneath the nest, as would invariably happen 



