CHAPTER III.
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
6o The Naturalist in La Plata.
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 maintained.