BOTH BIRDS INCUBATING. 235 



tion and attention : he, too, as abundantly feeds his 

 mate during the time of incubation, and occasion- 

 ally relieves her by taking her place upon the eggs. 

 This is also the case with the ring-dove, whose 

 cooing notes are among the sweetest of country 

 sounds ; the male and female sit by turns while 

 hatching, and, when the young are hatched, alter- 

 nately feed them. Other species of the Colum- 

 bida3 are remarkable for the same actions. Of 

 the American crow, Audubon says, "both sexes 

 incubate, and their parental care and attachment 

 are not surpassed by those of any other bird." 



It seems not improbable that the cause of this 

 constant incubation may be in the risk of too long 

 exposure of the eggs in sueh cold situations as are 

 selected by these birds for their nests. It will be 

 easily conceived how much exposed the eggs of a 

 dove must be, placed as they are upon a shallow 

 platform at the summit of a tall tree. Perhaps, 

 therefore, the constant application of warmth is 

 rendered necessary by this circumstance, in these 

 instances. Yet, in the case of the warblers, the 

 nest is well concealed, even more so than in that of 

 other birds, so that a general rule cannot be made 

 out from the facts before us. 





