298 
ANIMAL INTELLIGENCE. 
of this large body of water from the second pond caused a rise 
of several inches, so as to threaten the speedy immersion and 
consequent destruction of the eggs. This the birds seem to 
have been aware of, and immediately took precautions against 
so imminent a danger ; for when the gardener, upon whose 
veracity I can safely rely, seeing the sudden rise of the water, 
went to look after the nest, expecting to find it covered and the 
eggs destroyed, or at least forsaken by the hen, he observed, 
whilst at a distance, both birds busily engaged about the brink 
where the nest was placed ; and when near enough he clearly 
perceived that they were adding, with all possible despatch , fresh 
materials to raise the fabric beyond the level of the increased 
contents of the pond : and that the eggs had by some means 
been removed from the nest by the birds, and were then de- 
posited upon the grass about a foot or more from the margin of 
the water. He watched them for some time, and saw the nest 
rapidly increase in height ; but I regret to add that he did not 
remain long enough, fearing he might create alarm, to witness 
the interesting act of replacing the eggs which must have 
been effected shortly after ; for, upon his return in less than an 
hour, he found the hen quietly sitting upon them in the newly 
raised nest. In a few days afterwards the young were hatched, 
and, as usual, soon quitted the nest and took to the water with 
their parents. The nest was shown to mem situ shortly after, 
and I could then plainly discern the formation of the new with 
the older part of the fabric. 
We must not conclude these remarks on nidification 
without alluding to Mr. Wallace’s chapters on the 4 Philo- 
sophy of Birds’ Nests,’ in his work on 4 Natural Selection.’ 
This waiter is inclined to suppose that birds do not build 
their nests distinctive of their various species by the teach- 
ings of hereditary instinct, but by the young birds intelli- 
gently observing the construction of the nests in which 
they are hatched, and purposely imitating this construc- 
tion when in the following season they have occasion to 
build nests of their own. With reference to this theory 
it is only needful to say that it is antecedently improbable, 
and not well substantiated by facts. It is antecedently 
improbable becaus°, when any habit has been continued 
for a number of generations — especially when the habit 
is of a peculiar and detailed character — the probability is 
that it has become instinctive ; we should have almost as 
