"Morning and evening," writes Schomburgk, "countless multitudes may be seen at a considerable height, making an insufferable noise; one afternoon I saw such a prodigious flight descend upon the trees by the river-side, that the branches bent low under the weight of the birds." "It is necessary to have lived in these countries, more especially in the hot valleys of the Andes," says Humboldt, "to believe it possible that the shrieking of the parrots actually drowns the roar of the mountain torrents as the waters leap from rock to rock. What would those wondrous tropical forests be without parrots? Lifeless gardens of enchantment, a wilderness of silence, a solitary desert; by these birds they are awakened and kept alive, for the parrots know equally well how to find occupation both for the ear and eye of the traveller." Except in the breeding season, parrots live in society, or, we might rather say, in great flocks; they select a locality in the forest as their settlement, and thence make daily excursions to considerable distances. Early in the morning they simultaneously quit their roosting-place, to invade the same tree or the same field in search of food, stationing sentinels, whose duty it is to protect the community from a sudden surprise. They pay instant attention to any voice of warning, and when alarmed, immediately take flight, either all together or shortly after each other. "At the first glimmering of the clear morning sun of the tropics," says the Prince von Wied, "the parrots rouse themselves from their sleeping-places, dry their wings, which have become wetted with the dews of night, and playfully call aloud to each other; then, after describing many sweeping circles above the high woods, they quickly depart in search of the morning's meal. In the evening they invariably come back again to their usual roost."