OBSERVATIONS ON CANADIAN BIRDS. IBY 
hatched in less time than the others, and that the female being 
obliged to leave the nest to provide for the wants of the youngster, 
the unhatched eggs are exposed to the weather, and do not come to 
maturity, but, in a few days, disappear altogether, leaving the intruder 
in undisputed possession of the nest. It has ever been a puzzle to 
naturalists to account for this singular habit, and as it may be interest- 
ing to hear what has been said on the subject, I will here make one 
or two short extracts. 
Wilson, after devoting more space to the description of this than any 
other bird he met with, says, ‘‘ what reason nature may have for this ex- 
traordinary deviation from the general practice, is, I confess, altogether 
beyond my comprehension. Many conjectures, indeed, may be formed 
as to the probable cause, but all of them, which have occurred to me, 
are unsatisfactory and inconsistent. Future and more numerous 
observations may throw some light on the matter, till then, we can 
only rest satisfied with the fact.” Mr. Selby, the eminent English 
naturalist, suggests, regarding this habit in the Cuckoo, that the old 
birds retire to the south before the young are able to accompany 
them, and therefore they have to be confided to the care of others. 
The writer of an article on this subject, in the British Cyclopedia of 
Natural History, says regarding Mr. Selby’s theory, ‘this is perhaps 
about as good an explanation of the Cuckoo’s peculiarities as has yet 
been offered, but it fails, like all the others, in being quite inapplicable 
to the North American Cow Bunting. The true cause, whatever 
that may be, of this extraordinary deviation, must, we are persuaded, 
be the same in both, nor can we at present accept of any explanation 
as satisfactory, which will not alike apply to either.” 
I have been particular in making these extracts, because it occurs 
to me that an important consideration connected with the subject has 
been overlooked, it is one which applies alike to the Cuckoo and the: 
Cowbird, and will, I think, if carefully followed up, go far to explain the 
seemingly unnatural conduct of both species. We recognize in it, as in 
accordance with the all wise laws which regulate animated nature, that 
over each class there is imposed a salutary check, to prevent excess in 
production ; this is specially observable among the feathered tribes, 
some of which have their eggs carried away by the ship-load from the 
breeding places; others, such as the grouse and waterfowl, are greatly 
reduced in number by sportsmen, or those who make a business of 
sending them to market, while the finches and blackbirds contribute 
