PRESIDENT S ADDRESS. 
5 
own nidification; this would hardly apply to those species 
that do not arrive at maturity before three years, as generally 
they do not associate with the adult breeding birds, but 
congregate together in Hocks, away from the nesting stations. 
If this imitation tendency is so powerful, how is it that the 
kestrel has never developed nest building, although Nature 
has endowed her with the same means or tools in the way of 
beak and claws as the sparrow hawk ? but instead of con¬ 
structing a nest of her own she makes use of an old or 
deserted one of a crow. The young kestrels, while in the 
nest, cannot possibly know the nest was not constructed by 
their parents, therefore this propensity of using another’s 
nest must surely be put down to inherent instinct. Some 
no doubt will say that an ancient pair of kestrels, more 
advanced in wisdom than their fellows, adopted the plan of 
utilising deserted nests in years gone by, and that their 
descendants follow their example at the present time ; but 
how would it be possible for the original wise pair to impart 
their knowledge to their offspring ? 
Again, why should not the cuckoo develop a propensity 
to construct a nest similar to that in which it was reared? I 
say, simply because it would be contrary to its inherent 
instinct. But it is argued that supposing a young cuckoo is 
brought up in a wagtail’s nest, that individual would in the 
future look out for a wagtail’s nest to deposit her eggs in 
likewise ; but supposing the young cuckoo proved a male—I 
believe males largely preponderate—the desire to use a nest 
of the same species must end in this case, as the male 
cuckoo takes no part whatever in domestic duties ; the trans¬ 
mitting of this trait must, therefore, rest entirely with the 
female bird. The consequence of this would be to very 
much restrict the number of species whose nests are used by 
the cuckoo, whereas the contrary is the case, as each year 
fresh species are added to the list in which a cuckoo’s egg has 
been found. 
If this imitation theory is correct, how are we to account 
for a cuckoo’s egg being found in the nest of Podiceps minor? 
such find being on record; because it would be an impossi¬ 
bility for a cuckoo to be reared by such foster parents. 
Whence, then, had the parent cuckoo her desire to deposit 
her egg in such an unsuitable nest ? 
It has always been a mystery to me how the cuckoo is 
able to ascertain if incubation has proceeded in the eggs of 
the bird she wishes to use as a foster parent for her progeny, 
because 1 have generally found that the legitimate eggs as 
well as the alien one hatch almost simultaneously. Various 
