Observations on the Cuckoo. 467 
prey upon eggs, from destroying them.* 
The chief objection to this supposition arises 
from the deficiency of evidence in support of 
_ this charge brought against the males. 
According to the Physiognomical System 
of Drs. Gall and Spurzheim, cuckoos trans- 
fer the care of their progeny to strangers, in 
consequence of the imperfect developement of 
certain cerebral organs, termed by these au- 
thors, organs of constructiveness and_philo- 
progenitiveness, whose functions are thts 
necessarily circumscribed. I shall not here 
discuss the merits of this system, which, not- 
withstanding the ridicule that is bestowed 
upon if, is at least entitled to a patient and 
candid investigation, but shall proceed. to 
consider the reason assigned by Mr. Jenner 
for the singularities of the cuckoo, which 
to me appears perfectly satisfactory. This 
gentleman conjectures, as [ have already 
stated, that the short stay which cuckoos 
make in this country is the true reason why 
they donot bring up their own young, as the 
parent birds would be impelled by a propen- 
sity to migrate, to quit their progeny before 
they were able to provide for themselves. 
This, as far as regards the British species, 
certainly seems to be a very sufficient cause: 
* Histoire Naturelle des Oiseaux, Tome sixieme. 
