Again, the regular nest of the house-martin is
hemispheric; but where a rafter, or a joist, or a cornice may happen
to stand in the way, the nest is so contrived as to conform to the
obstruction, and becomes flat or oval, or compressed.
In the following instances instinct is perfectly uniform and
consistent. There are three creatures, the squirrel, the field-mouse,
and the bird called the nut-hatch (sitta Europaea), which live much
on hazel nuts; and yet they open them each in a different way. The
first, after rasping off the small end, splits the shell in two with his
long fore-teeth, as a man does with his knife; the second nibbles a
hole with his teeth, so regular as if drilled with a wimble, and yet
so small that one would wonder how the kernel can be extracted
through it; while the last picks an irregular ragged hole with its bill:
but as this artist has no paws to hold the nut firm while he pierces
it, like an adroit workman, he fixes it, as it were in a vice, in some
cleft of a tree, or in some crevice; when, standing over it, he
perforates the stubborn shell.
Pages:
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409