THE COW BLACKBIRD. 165 



Wilson and Audubon, as well as the earlier ornithologists 

 in general, were mistaken in saying that no nest contained 

 more than one of the Cow Blackbird's eggs. I have fre- 

 quently found more than one in the same nest; once not 

 less than four in the nest of a Scarlet Tanager, which had 

 only room enough left for two of her own. Mr. Trippe 

 once found a Black-and-white Creeper's nest with five of 

 the eggs of the interloper and three deposited by the owner. 

 Dr. Coues has well said: "We may consider this pair of 

 Creepers relieved, on the whole, by Mr. Trippe's visit the 

 mother-bird rescued from drowning in the inundation of so 

 many 'well-springs,' and the father saved the necessity of 

 hanging himself from the nearest convenient crotch." 



Perhaps requiring a shorter period of incubation, perhaps 

 on account of the size of the egg being greater, and thus 

 receiving more warmth than those of the owner of the nest, 

 the Cow Bird's egg invariably hatches first. Then the 

 foster parent, prompted by the generosity of parental in- 

 stinct, will leave her own eggs to chill, while she secures food 

 for the foundling. Thus the Cow Bird alone is hatched, 

 and the addled eggs of the owner of the nest are soon 

 removed. Considering the number of nests thus intruded 

 upon, sometimes apparently more than half of the small 

 birds' nests in this locality, the check thus put upon 

 the propagation of these various species must be very 

 great. 



The young Cow Blackbird grows rapidly, and soon more 

 than fills the nest. Meanwhile the foster parents feed it 

 most assiduously, and continue to do so long after it has 

 left the nest, and when it is many times larger than the 

 little Sparrow or Warbler thus imposed upon. It is by no 

 means suggestive of pleasing reflections to see this great 

 over-grown foundling flapping its wings and calling loudly 



