408 ORIGIN OF SPECIES 



ment of small birds, and these seemed perfect, and some of 

 them, which were tried, germinated. But the following fact 

 is more important: the crops of birds do not secrete gastric 

 juice, and do not, as I know by trial, injure in the least the 

 germination of seeds; now, after a bird has found and de- 

 voured a large supply of food, it is positively asserted that 

 all the grains do not pass into the gizzard for twelve or even 

 eighteen hours. A bird in this interval might easily be 

 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, mil- 

 let, canary, hemp, clover, and beet germinated after having 

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

 different birds of prey ; and two seeds of beet grew after hav- 

 ing 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 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 visted 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 



