464 Observations on the Cuckoo. 
playing symptoms of debility and torpor, con- 
tinue to advance progressively in growth and 
vigour. Cuckoos, at a mean of ten years’ 
observations, appear in this neighbourhood on 
the 22nd of April, when the temperature of 
the air is 48° in the shade, and quit it on the 
26th of June, when the temperature is 57°. 
It has been asserted, that cuckoos some- 
times incubate their own eggs, and bring up 
their own young; but all theinstances brought 
forward in support of this opinion, except one, 
are totally undeserving of notice; and this 
might have been passed over without comment 
also, if Dr. Darwin, * the Hon. Daines Bar- 
rington,t and the Rev. W. Bingley,{ had 
not seemed to consider it conclusive and in- 
controvertible. 'The circumstance is thus re- 
lated by Darwin. ‘“ As the Rev. Mr. Staf- 
ford was walking in Glossop Dale, in the Peak 
of Derbyshire, he saw a cuckoo rise from its 
nest. The nest wason the stump of a tree, 
that had been some time felled, among some 
chips that were in part turned grey, so as 
much to resemble the colour of the bird. In 
this nest were two young cuckoos: tymg a 
* Zoonomia, Vol. 1. p. 172-3. 
; 
+ Miscelianies, p. 255. 
\} Animal Biography, Vol. 11. p. 299, 300. 
