Page:Popular Science Monthly Volume 30.djvu/626

604 Strawberries are a choice delicacy for the wood-hen, and their seeds are minute enough to escape being ground up among the millstones of its crop. The fowls, therefore, unknowingly sow the seeds in the forest along with their dung, and help the plant to find new beds in fresh soil. Geese are especially fond of the leaves of Potentilla anserina, and with them eat multitudes of the minute seeds of the plant. Thereby, while the natural home of the potentilla is by brooks, it is transplanted by the geese to quite different localities; and in mountainregions, where nearly all the towns are on little streams, the potentillais to be found as far away in the neighboring fields and along the borders of the woods as the geese are driven in the fall to feed upon the stubble.

When the Spaniards settled in Chili they brought with them their native apple and other fruit-trees. The fruits of these orchards, which were planted, of course, only in the neighborhood of dwellings, were fallen upon by the native parrots, and they carried the apples and undigested seeds into all parts of the country, so that the traveler may now find whole forests of wild apple-trees in places which have received no other touch of human cultivation. In a similar way crows have spread the opuntia over the uninhabited islands of the Canaries, and the nut-crackers in the Alps the seeds of the vetch in places where the winds and man could never have carried them.

Not a few birds are impelled, by the instinct to get their food in as much security as possible, to form relations with other animals. Starlings are found frequently associated with flocks of sheep, making themselves at home on their backs and playing the part of selfish benefactors of the suffering animals as they explore their wool for appetizing ticks and lice. So there are birds, according to eminent travelers, in Africa that perform similar service for elephants, camels, horses, the rhinoceros, and the hippopotamus. These prudent and vigilant birds are ever to be found in company with their huge providences, and give the sleeping monsters timely warning, with their shrill, familiar cries, of approaching danger. Lichtenstein relates that ostriches and zebras are on good terms with one another, to their mutual profit. The droppings of the zebra afford a breeding-ground for innumerable beetle-grubs, and these are a choice delicacy to the ostriches. When any danger approaches the company—if, for instance, a horseman appears in the distance—it is at once perceived by the tall, sharp-eyed birds, which take to flight in a direction away from the threatening object; and the dull-sighted zebras, without knowing what is really going on, sagaciously intrust themselves to the guidance of their careful associates. Similar harmonies in behavior may be observed among animals in very remote quarters of the world—between the rheas and the stags and guanacas of Brazil, and between the royal pheasant and the wild goat of the Caucasus. The ancients had a story of a bird—the trochilus—which made its living by picking the teeth of the