Ch. 3: A Wave of Life

For many years, while living in my own home on the pampas, I kept a
journal, in which all my daily observations on the habits of animals and
kindred matters were carefully noted. Turning back to 1872-3, I find my
jottings for that season contain a history of one of those waves of
life--for I can think of no better name for the phenomenon in
question--that are of such frequent occurrence in thinly-settled
regions, though in countries like England, seen very rarely, and on a
very limited scale. An exceptionally bounteous season, the accidental
mitigation of a check, or other favourable circumstance, often causes an
increase so sudden and inordinate of small prolific species, that when
we actually witness it we are no longer surprised at the notion
prevalent amongst the common people that mice, frogs, crickets, &c., are
occasionally rained down from the clouds.

In the summer of 1872-3 we had plenty of sunshine, with frequent
showers; so that the hot months brought no dearth of wild flowers, as in
most years. The abundance of flowers resulted in a wonderful increase of
humble bees. I have never known them so plentiful before; in and about
the plantation adjoining my house I found, during the season, no fewer
than seventeen nests.

The season was also favourable for mice; that is, of course, favourable
for the time being, unfavourable in the long run, since the short-lived,
undue preponderance of a species is invariably followed by a long period
of undue depression. These prolific little creatures were soon so
abundant that the dogs subsisted almost exclusively on them; the fowls
also, from incessantly pursuing and killing them, became quite rapacious
in their manner; whilst the sulphur tyrant-birds (Pitangus) and the
Guira cuckoos preyed on nothing but mice.

The domestic cats, as they invariably do in such plentiful seasons,
absented themselves from the house, assuming all the habits of their
wild congeners, and slinking from the sight of man--even of a former
fireside companion--with a shy secrecy in their motions, an apparent
affectation of fear, almost ludicrous to see. Foxes, weasels, and
opossums fared sumptuously. Even for the common armadillo (Dasypus
villosus) it was a season of affluence, for this creature is very adroit
in capturing mice. This fact might seem surprising to anyone who marks
the uncouth figure, toothless gums, and the motions--anything but light
and graceful--of the armadillo and perhaps fancying that, to be a
dexterous mouser, an animal should bear some resemblance in habits and
structure to the felidas. But animals, like men, are compelled to adapt
themselves to their surroundings; new habits are acquired, and the exact
co-relation between habit and structure is seldom