304 
ANIMAL INTELLIGENCE. 
the cuckoo % May they not be owing to the following circum- 
stances, — the short residence this bird is allowed to make in 
the country where it is destined to propagate its species, and 
the call that nature has upon it, during that short residence, 
to produce a numerous progeny % The cuckoo’s first appearance 
here is about the middle of April, commonly on the 17th. Its 
egg is not ready for incubation till some weeks after its arrival, 
seldom before the middle of May. A fortnight is taken up by 
the sitting bird in hatching the egg. The young bird generally 
continues three weeks in the nest before it flies, and the foster- 
parents feed it more than five weeks after this period ; so that, 
if a cuckoo should be ready with an egg much sooner than the 
time pointed out, not a single nestling, even one of the earliest, 
would be fit to provide for itself before its parent would be in- 
stinctively directed to seek a new residence, and be thus com- 
pelled to abandon its young one ; for old cuckoos take their 
final leave of this country the first week in July. 
Had nature allowed the cuckoo to have stayed here as long 
as some other migrating birds, which produce a single set of 
young ones (as the swift or nightingale, for example), and had 
allowed her to have reared as large a number as any bird is 
capable of bringing up at one time, there might not have been 
sufficient to have answered her purpose ; but by sending the 
cuckoo from one nest to another, she is reduced to the same 
state as the bird whose nest we daily rob of an egg, in which 
case the stimulus for incubation is suspended. 
A writer in 6 Nature ’ (vol. v., p. 383 ; and vol. ix., p. 
123), to whom Mr. Darwin refers in the latest edition of 
6 The Origin of Species ’ as an observer that Mr. Gfould has 
found trustworthy, precisely confirms, from observations 
of his own, the above description of Jenner. So far, 
therefore, as the observations are common I shall not 
quote his statements ; but the following additional matter 
is worth rendering: — - 
But what struck me most was this : the cuckoo was per- 
fectly naked, without a vestige of a feather or even a hint of 
future feathers ; its eyes were not yet opened, and its neck 
seemed too weak to support the weight of its head. The pipits 
(in whose nest the young cuckoo was parasitic) had well- 
developed quills on the wings and back, and had bright eyes 
partially open ; yet they seemed quite helpless under the mani- 
pulations of the cuckoo, which looked a much less developed 
