82 UPLAND AND MEADOW. 



as are subjected to the annoyance of the cowpen bird's 

 egg being deposited in their nests. I was surprised at 

 this result, and am led to believe that large numbers of 

 the eggs of this bird are destroyed. It is well-known 

 that our summer warbler frequently outwits the cowpen 

 bird by building a new nest directly above the old — a 

 two-story nest, in fact — leaving the egg that has been 

 left to her care to rot in the basement, while she rears 

 her young on the floor above. It will be seen that from 

 these experiments no very positive results were obtained. 

 I did note, however, that, where the change was accept- 

 ed, it was not because it passed unnoticed, but was sub- 

 mitted to, notwithstanding the evidences of much mis- 

 giving on the part of the birds. In one case, the nest 

 was practically deserted for twenty-four hours, and the 

 eggs were chilled in consequence. The birds sat upon 

 them for five days, when, as they did not hatch, the 

 nest was abandoned. In previous years I have made 

 these changes occasionally with success, but was not 

 able to determine that the young were recognized as 

 not the offspring of the attendant birds. In such cases 

 the young were tended with the usual care up to the 

 time for leaving the nest. This may possibly be indica- 

 tive of stupidity. It appeared so to me at the time; 

 but I am now disposed to see in it an indication that 

 the maternal instincts here, as in other cases I have men- 

 tioned, overcame all other feelings, and that the fact 

 was accepted by the birds with as good grace as they 

 could command. 



The co-operation of birds, when constructing their 

 nests, is a subject that demands a good deal of close at- 



