The Cowbird 151 



the search for the nest of some other bird in which to deposit 

 it. When this is done she returns to her associates and gives 

 no further attention to the egg or the young that will be 

 hatched from it. She is entirely devoid of maternal affection 

 and love. As a rule the eggs are deposited in the nests of the 

 smaller birds. The illustration accompanying this chapter 

 shows the nest of a vesper sparrow 'with three speckled eggs 

 of that sparrow and one large one of the cowbird. Major 

 Bendire has listed ninety-one different kinds of birds in whose 

 nests cowbirds' eggs were found and of these only thirteen 

 were larger than the cowbird and at least three-fourths of 

 them were smaller, the sparrows, vireos and warblers being 

 the greatest sufferers. The evident reason why the cowbird 

 selects the nests of the smaller birds is that the young of the 

 foster parents may perish and its own survive. Remembering 

 that the eggs of the cowbird hatches in ten to eleven days, and 

 generally in advance of those of the foster parents, it is easy 

 to understand why this is so. 



In The Oologist of August, 1893, Mr. M. A. White tells 

 of an experiment with a chipping sparrow and a cowbird's 

 egg. "It was," he says, "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. I watched results. About the 19th Mr. 

 Cowbird 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 foster 

 brother. The other egg failed, to hatch. The daily increase in 

 the size of the cowbird was something immense, while the 

 younger companion seemed to diminish rather than enlarge, 

 until finally, at the end of three days, he died, evidently for 

 want of food, as the cowbird, being the larger, greedily de- 

 voured everything that came in contact with his capacious 

 mouth." Major Bendire in commenting upon this communica- 

 tion says : "Such seems to be the fate of nearly all the young 

 which have the misfortune to be hatched with a cowbird for a 

 companion. I have yet to see a nest containing young birds 

 of both species more than a few days old; by that time the 

 rightful offspring are smothered or crowded out of the nest 



