INDIRECT BENEFITS DERIVED FROM INSECTS. 199 



One of the most important ends for which insects were gifted with such 

 powers of multiplication, giving birth to myriads of myriads of individuals, 

 was to furnish the feathered part of the creation with a sufficient supply of 

 food. The number of birds that derive the whole or a principal part of 

 their subsistence from insects is, as is universally known, very great, and 

 includes species of almost every order. 



Amongst the Accipitres the kestril (Falco tinnunculus L.) devours 

 abundance of insects. A friend of mine, upon opening one, found its 

 stomach full of the remains of grasshoppers and beetles, particularly the 

 former, which he suspects constitute great part of the food of this species. 

 One of the shrikes, also, or butcher-birds (^Lanius collurio) — and it is pro- 

 bable that other species of this numerous genus may have the same habits — 

 is known to feed upon insects, which it first impales alive on the thorns of 

 the sloe and other spinous plants, and then devours. If meat be given it, 

 when kept in a cage, it will fix it upon the wires before it eats it. Lanius 

 excubitor also impales insects ; but Heckewelder denies that it feeds upon 

 them. If he be correct, the object of this singular procedure with that 

 species may be to allure the birds which it preys upon to a particular spot. ^ 



Amongst the Piece or Pies the Crotophaga, called the Ani, which is a 

 native of Africa and America, lives upon the locust and Ixodes ricinus, 

 which it picks in great numbers from the backs of cattle ; but none are 

 greater devourers of insects in this order than rooks. It is for the grubs 

 of Melolontha Tipula, &ic,, that they follow the plough ; and they always 

 frequent the meadows in which these larvae abound, destroying them in 

 vast numbers. Kalm tells us, that when the little crow was extirpated 

 from Virginia at an enormous expense, the inhabitants would willingly 

 have brought them back again at double the price.^ The icteric oriole is 

 kept by the Americans in their houses for the sake of clearing them 

 of insects; and the purple grackle is so useful in this respect, that when, 

 on account of their consuming grain, the American farmers in New Eng- 

 land offered a reward of threepence a head for them, and they were in 

 consequence nearly extirpated, insects increased to such a degree as to 

 cause a total loss of the herbage, and the inhabitants were obliged to 

 obtain hay for their cattle not only from Pennsylvania, but even from 



' According to Mr. Heckewelder (Trans. Amer. Phil. Soc. iv. 124.), L. excubitor, called 

 in America the nine-killer, from an idea that it transfixes nine individuals daily, treats in 

 this manner Grnsshnppers only ; while L. collurio would seem to restrict itself chiefly to 

 Geotrvpea, two of which Mr. Sheppard once observed transfixed in a hedge that he knew to 

 be the residence of this bird. Kugellan even thinks that it impales only G. vernalis, which 

 he has often found transfixed, but never G. stercorarius. (Schneid. Mag. 259.) I must 

 remark, however, that I last summer observed two humble-bees quite alive impaled on the 

 thorns of a hedge near my house, which had most probably been so placed by this spe cies, 

 L. excubitor being rarely found except in mountainous wilds. (Bewick's Birds, i. 61.) 

 And Prof. Sander states that on opening this bird (L. collurio) he has sometimes found in 

 its stomach nothing but grasshoppers, and at others small beetles and other insects. 

 {Naturfurscher, Slk. xviii. 234.) Mr. Dunlop, in a letter in Loudon's Gardener's Magazine 

 for May, 1812, (No. cxlvi. p. 250.), states, that upon examining a branch of hawthorn on 

 which he had for some days observed a pair of fly-catchers feeding their young, he found 

 upwards of a dozen humble-bees {Bombus terrestris) fixed upon the spines as securely as if 

 done by the hand of man, some being alive, and others dead and partly devoured. Mr. 

 Dunlop, after removing the bees to watch the process of the birds in placing them, bad soon 

 the satisfaction of seeing the fly-catchers catch them on the wing, carry them direct to the 

 branch (which was a dead one, apparently on account of the greater hardness of the 

 spines), and thrust them on the spines as above described. Mr. W. W. Saunders found a 

 number of the yellow underwing moth {Triphmna pronuba) thus fixed. 



« Stillingfl. Tracts, 175. Linn. Trans, v. 105. note b. 



