(2) "Driving" during the day (available only in dry years). (3) Awaiting their arrival at dusk at their _dormideros_, or sleeping-places, see pp. 97, 98. An all-important factor in their pursuit arises from an economic necessity with wild-geese constantly to possess, and frequently to renew, a store of sand or grit in their gizzards. To obtain this they resort every morning to certain sandy spots in the marismas (hereinafter described, and which are known as _vetas_); or failing that, when the said _vetas_ are submerged, to the sand-dunes outside. Although great numbers of geese resort each morning to these spots, yet those numbers are but a small proportion of their entire aggregate, for no individual goose needs to replenish his supply of sand or grit more often than perhaps once a week, or even less frequently. Hence at each dawn it is a fresh contingent of geese that comes in _para arenárse_ = to "sand themselves," as our keepers put it. One other quality in the natural economy of wild-geese requires mention--that is, their sense of scent. This defence wild-geese possess in equal degree with wild-ducks and most other wild creatures; but each class differ in their modes of utilising it. For whereas ducks on detecting human scent will take instant alarm and depart afar on that indication alone; yet geese, on the other hand, though their nostrils have fully advised them of the presence of danger, will not at once take wing, but remain--with necks erect and all eyes concentrated towards the suspect point--awaiting confirmation by sight what they already know by scent. That such is the case we ascertained in the days (now long past) when we ventured to stalk geese with no more covert than the low fringe of rush that borders the marisma. "_Gatiando_" = cat-crouching, our keepers term the method--laborious work, creeping flat for, it may be, 200 yards, through sloppy mud with less than two-foot of cover. Should it become necessary during the stalk to go directly to windward of the fowl, one's presence (though quite unseen) would be instantly detected. The geese, ceasing to feed or rest, all stood to attention, while low, rumbling alarm-signals resounded along their lines. But they did not take wing. Presently, however, one reached a gap in the thickly growing rushes--it might not extend to a yard in width, yet no sooner was but a glimpse available to the keen eyes beyond, than the whole pack rose in simultaneous clatter of throats and wings. They had merely waited that scintilla of ocular confirmation of a known danger. "DRIVING" (IN A DRY SEASON) For four months no rain had fallen. The parched earth gaped with cavernous cracks; vegetation was dried up; starving cattle stood about listless, and every day one saw the assembled vultures devouring the carcases of those already dead.