Chap. ZH.] MEANS OF DISPERSAL. 327 



has found and deovured a large supply of food, it is positively 

 asserted that all the grains do not pass iDto the gizzard for twelve 

 or even eighteen hours. A hird in this interval might easily bo 

 blown to the distance of 500 miles, and hawks are known to look 

 out for tired birds, and the contents of their torn crops might thus 

 readily get scattered. Some hawks and owls bolt their prey whole, 

 and, after an interval of from twelve to twenty hours, disgorge 

 pellets, which, as I know from experiments made in the Zoological 

 Gardens, include seeds capable of germination. Some seeds of the 

 oat, wheat, millet, canary, hemp, clover, and beet germinated aftei 

 having been from twelve to twenty-one hours in the stomachs of 

 different birds of prey; and two seeds of beet grew after having 

 been thus retained for two days and fourteen hours. 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 trans- 

 ported 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 excre- 

 ment ; 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 Ecv. E. 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 

 upwards 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. They 

 then disappeared over the sea, as suddenly as they had appeared, 

 and have not since visited the island. Now, in parts of Natal it is 

 believed by some farmers, though on insufficient evidence, that 

 injurious seeds are introduced into their grass-land in the dung left 

 by the great flights of locusts which often visit that country. In 

 consequence of this belief Mr. Weale sent me in a letter a small 

 packet of the dried pellets, out of which I extracted under the 

 microscope several seed3, 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. 



