Positions of Birds' Nests in Hedges

Abstract

LIEUT.-COLONEL TULL WALSH'S observations as to the positions of nests (NATURE, December 16) are interesting, as they tally with the aspect of arboreal cryptogams, as already noted by me. South-west winds depositing sulphurous and nitrous products to leeward of towns cause lichens and mosses to flourish best on the eastern side of trees and hedges; and, moreover, this is general, for winds bearing spores from the south-west continually play on the trunks and blow away spores as they settle. If it were not for a kind of capillary attraction or rotary motion drawing the spores round the trunk to leeward, or east or north-east, they would never germinate. So the eastern side is the most productive, though often the western aspect may exhibit a greater abundance of species, though less well developed, from the continuous play of spores—and rain—upon the trunk.