190 COW BUNTING. 



" my first visit I found a young Cow-bird, and three eggs re- 

 " maining. I took the eggs out; two contained young birds ap- 

 " parently 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 

 66 of life being discoverable in either. 



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



OO 



" each only, and I attended it carefully till the usual comple- 

 " ment 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 

 tf 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 in- 

 " stances could I ascertain exactly the time required to hatch 

 " the Cow-bird's eggs; and that of course none of them are de- 

 " cisive; 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 ele- 

 " vated 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 Blue-bird's nest in 

 " the hollow stump, the cavity was a foot deep, the nest at 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 cir- 

 cumference, and vice versa, that all of them may receive an equal share of 

 warmth. 



