INSECTS ON BIRDS. 159 



with all birds of prey.* When owls fly, they stretch out 

 their legs behind them, as a balance to their large heavy 

 heads ; for, as most nocturnal birds have large eyes and ears, 

 they must have large heads to contain them. Large eyes, 

 I presume, are necessary to collect every ray of light, and 

 large concave ears to command the smallest degree of sound 

 or noise. 



The hirundines are a most inoffensive, harmless, entertain- 

 ing, social, and useful tribe of birds ; they touch no fruit in 

 our gardens ; delight, all except one species, in attaching 

 themselves to our houses ; amuse us with their migrations, 

 songs, and marvellous agility : and clear our outlets from the 

 annoyances of gnats and other troublesome insects. Some 

 districts in the South Seas, near Gruiaquil,t are desolated, it 

 seems, by the infinite swarms, of venomous mosquitoes, which 

 fill the air, and render those coasts insupportable. It would 

 be worth inquiring, whether any species of hirundines is 

 found in these regions. Whoever contemplates the myriads 

 of insects that sport in the sunbeams of a summer evening in 

 this country, will soon be convinced to what a degree our 

 atmosphere would be choked with them were it not for the 

 friendly interposition of the swallow tribe. J 



* All birds of prey are capable of sustaining the want of food and water for 

 long periods, particularly the latter, but of which they also seem remarkably 

 fond, drinking frequently in a state of nature, and, during summer, washing 

 almost daily. TV. J. 



t See Ulloa's Travels. 



J This passage alone ought to be sufficient to prevent persons from wantonly 

 destroying this useful, engaging, and elegant bird. If they were more encou- 

 raged than they are about hop-grounds, suitable erections being made, against 

 which they would build, the editor is convinced that much of the blight so 

 common on the bind of hops would be prevented. Mr. Knapp, in his Journal 

 of a Naturalist, remarked, that the immense quantity of flies destroyed in a 

 short space of time, by one individual bird, is scarcely to b& credited by those 

 who have not actual experience of the fact. He adds, that he was once present 

 when a swift was shot. It was in the breeding season, when the young were 

 hatched, at which time the parent birds are in the habit of making little 

 excursions into the country, for the purpose of collecting flies, which they 

 bring to their infant progeny. He says, that on picking up the bird, he 

 observed a number of flies, some mutilated, others scarcely injured, crawling 

 out of the bird's mouth. The throat and pouch seemed absolutely stuffed 

 with them, and an incredible number was at length disgorged. He thinks 

 that he is within compass in stating, that there was a mass of flies, just caught 

 by this single swift, larger than, when pressed close, would conveniently be 

 contained in the bowl of an ordinary table-spoon. ED. 



