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 
“ 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 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 
“ 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 aU 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. 
