460 Observations on the Cuckoo. 
the area of England and Wales is 49,450 
square miles; which reduced to square yards 
gives 153,176,320,000. This, divided by 
8,301,816 square yards, the area of the town- 
ship of Crumpsall, and the quotient multi- 
plied by 3, the mean number of hen cuckoos 
for every 3,301,816 square yards, gives 
139,173, the mean annual number of female 
cuckoos that visit England and Wales; which 
multiplied by 5, the mean number of eggs 
laid by the cuckoo, gives 695,865, the num- 
ber of nestlings produced annually by the 
mean number of females; and this product 
multiplied by 5, the mean number of eggs 
laid by those birds to whose care cuckoos 
usually intrust their offspring, gives 3,479, 
325, the mean annual number of nestling 
birds destroyed by young cuckoos in England 
and Wales. Enormous as this destruction 
appears, it is probably rather under than 
overrated, and when compared with that oc- 
casioned by cuckoos in general, or by our 
British species alone, in the various countries 
in which it breeds, it sinks into absolute in- 
significance. 
The injuries which so frequently ‘happen 
to the eggs of those birds in whose nests 
cuckoos lay, are occasioned, as I have often 
proved experimentally, by the sitting bird, 
