es
in shallow runs amongst the roots of herbage. Its exploits
are recorded in a Report on the Plague of Field-Mice in
Scotland, made by a committee appointed by the President of
the Board of Agriculture, 1893.

Two birds of North America, belonging to the Woodpecker family,
prepare their provisions for the bad season with consummate art; not
only do they harvest them and place them in shelter, but they arrange
them in such a manner that at the right moment they can utilise them
in the most convenient manner.

One of them which is common in California, the _Melanerpes
formicivorus_, nourishes himself, as his name indicates, by insects,
and especially ants. All the summer he gives himself up to this hunt,
but at the same time he collects acorns, which he does not touch,
however, so long as he can find other food. He amasses them in the
following ingenious manner: he chooses a tree and hollows out in its
trunk a cavity just capable of receiving one acorn. He then carries a
fruit and introduces it forcibly into the hole he has just made. Thus
buried, the acorn can neither fall nor become the prey of another
animal. In the domain of these birds trees may be found which are
riddled like a sieve with holes stopped up by an acorn as by a plug.
When the hunting of insects ceases to be fruitful, the _Melanerpes_
visits his barns. If an ordinary bird wished to eat one of these
fruits, at each stroke of his beak, on account of the polish and
convexity of the acorn's surface, it would escape him, and only by a
series of reiterated efforts would the interior be exposed; but for
the American woodpecker the task is simplified; each acorn being
maintained firmly in the bark, it is sufficient to break the envelope
and the pulp is easily seized.[51]

[51] See, for instance, _Nature_, 20th July 1871; also A. L.
Heermann, "Notes on the Birds of California," _Journ. Acad.
Nat. Sc. Philadelphia_, 2nd Series, vol. ii., 1853, p. 259.

A relation of this bird, the _Colaptes mexicanus_, does not yield to
him in economy and skill. He places his barn in the interior of a
plant which is very abundant in the zone he inhabits. Insectivorous
during a part of the year, he is forced to renounce this diet during
the dry season. In the regions of Mexico where this bird is found the
dry period is so absolute that he would die of hunger for want of
insects or fruits if he had not taken the precaution of