Page - 409 - in The Origin of Species

MEANS OF DISPERSAL 409 appeared, and have not since visited the island. Now, in parts of Natal it is believed by some farmers, though on in- sufficient evidence, that injurious seeds are introduced into their grassland in the dung left by the great flights of locusts v^'hich often visit that country. In consequence of this be- lief Mr. Weale sent me in a letter a small packet of the dried pellets, out of which I extracted under the microscope several seeds, and raised from them seven grass plants, belonging to two species, of two genera. Hence a swarm of locusts, such as that which visited Madeira, might readily be the means of introducing several kinds of plants into an island lying far from the mainland. Although the beaks and feet of birds are generally clean, earth sometimes adheres to them : in one case I removed sixty-one grains, and in another case twenty-two grains of dry argillaceous earth from the foot of a partridge, and in the earth there was a pebble as large as the seed of a vetch. Here is a better case : the leg of a woodcock was sent to me by a friend, with a little cake of dry eartli attached to the shank, weighing only nine grains ; and this contained a seed of the toad-rush (Juncus bufonius) which germinated and flowered. Mr. Swaysland, of Brighton, who during the last forty years has paid close attention to our migratory birds, informs me that he has often shot wagtails (Motacillae), wheatears, and whincats (Saxicolse), on their first arrival on our shores, before they had alighted ; and he has several times noticed little cakes of earth attached to their feet. Many facts could be given showing how generally soil is charged with seeds. For instance. Prof. Newton sent nie the leg of a red-legged partridge (Caccabis rufa) which had been wounded and could not fly, with a ball of hard earth adhering to it, and weighing six and a half ounces. The earth had been kept for three years, but when broken, watered and placed under a bell-glass, no less than 82 plants sprung from it: these consisted of 12 monocotyledons, includ- ing the common oat, and at least one kind of grass, and of 70 dicotyledons, which consisted, judging from the young leaves, of at least three distinct species. With such facts before us, can we doubt that the many birds which are annually blown by gales across great spaces of ocean, and which annually