Fresh-water fish, I find, eat seeds of many land and water plants; fish are frequently devoured by birds, and thus the seeds might be transported from place to place.

I forced many kinds of seeds into the stomachs of dead fish, and then gave their bodies to fishing-eagles, storks, and pelicans; these birds, after an interval of many hours, either rejected the seeds in pellets or passed them in their excrement; and several of these seeds retained the power of germination.
Certain seeds, however, were always killed by this process.
Locusts are sometimes blown to great distances from the land.

I myself caught one 370 miles from the coast of Africa, and have heard of others caught at greater distances.

The Rev.R.T.Lowe informed Sir C.Lyell that in November, 1844, swarms of locusts visited the island of Madeira.
They were in countless numbers, as thick as the flakes of snow in the heaviest snowstorm, and extended upward as far as could be seen with a telescope.

During two or three days they slowly careered round and round in an immense ellipse, at least five or six miles in diameter, and at night alighted on the taller trees, which were completely coated with them.