on the Mind of a Bird.



211



different families normally build tlieir nests; inherited habit

which obtains, as I have shewn, even after a lapse of hundreds

of years of domestication, during which time the natural instinct

has been in abeyance.


When a bird alters its method of building, there is always

a reason for the change. It is obvious that, in a crowded aviary,

where many birds may desire to nest simultaneously, it is an

advantage for many birds to build in boxes or prepared Hartz

travelling-cages, rather than in open bushes; in the former there

is only a front entrance to defend ; in the latter the owner of the

nest maybe molested from all sides. This is why, in my opinion,

many of the small finches prefer to build in such receptacles,

when associated with many other birds.


Even in their wild state various species of birds surround

their nests, with the exception of a narrow entry, with thorny

twigs; which offer a formidable protection against the inroads of

marauding enemies. Others, as recorded in various works by

travellers in different parts of the tropics, build their nests close

to the homes of particularly venomous wasps. In these cases,

however, we have inherited reason, which has therefore been

called instinct.


That birds differ considerably in their reasoning powers is

an unquestionable fact, the English House Sparrow being one of

the most weak-minded ; whereas some of the Crows, the Hang-

nests ( Icterus) and the Parrots, are among the most keen-witted.


In 1877 I wrote to Charles Darwin respecting a pair of

House-Sparrows which persisted in building their nest in a roller-

blind. Every morning the blind was lowered to shade the room

from the sun and the nest fell to the ground ; but no sooner was

the blind drawn up again than all the rubbish was replaced.

This continued for nearly a month, and it was only after two or

three wet days, which had enabled the birds to make considerable

progress, when the lowering of the blind again threw out the

materials, that they were convinced of the futility of their efforts.

Darwin’s reply to my letter is published in “ British Birds with

their Nests and Eggs,” vol. II., p. 87. On another occasion I

watched a female Passer domestictis attempting, for two hours, to

persuade a quill-feather, of probably a goose, to remain by itself



