CO W BUNTING. 299 



the process of incubation was going on. Three or four days 

 after my first visit, I found a young cow bird and three eggs 

 remaining. I took the eggs out ; two contained young birds, 

 apparently come to their full time, and the other was rotten. 

 I found one of the other eggs on the ground at the foot of the 

 stump, differing in no respect from those in the nest, no signs 

 of life being discoverable in either. 



" Soon after this I found a goldfinch's nest with one egg 

 of each only, and I attended it carefully till the usual com- 

 plement of the owner were laid. Being obliged to leave 

 home, I could not ascertain precisely when the process of 

 incubation commenced ; but from my reckoning, I think the 

 egg of the cow bird must have been hatched in nine or ten 

 days from the commencement of incubation. On my return, 

 I found the young cow bird occupying nearly the whole nest, 

 and the foster-mother as attentive to it as she could have 

 been to her own. I ought to acknowledge here, that in none 

 of these instances could I ascertain exactly the time required 

 to hatch the cow bird's eggs, and that of course none of 

 them are decisive ; but is it not strange that the egg of the 

 intruder should be so uniformly the first hatched ? The idea 

 of the egg being larger, and therefore from its own gravity 

 finding the centre of the nest, is not sufficient to explain the 

 phenomenon ; for in this situation the other eggs would be 

 proportionably elevated at the sides, and therefore receive as 

 much or more warmth from the body of the incumbent than 

 the other.* This principle would scarcely apply to the eggs 

 of the blue bird, for they are nearly of the same size; if there 

 be any difference, it would be in favour of the eggs of the 

 builder of the nest. How do the eggs get out of the nest ? 

 Is it by the size and nestling of the young cow bird ? This 

 cannot always be the case ; because, in the instance of the 



* The ingenious writer seems not to be aware, that almost all birds 

 are in the habit, while sitting, of changing the eggs from the centre to 

 the circumference, and vice versa, that all of them may receive an equal 

 share of warmth. 



