THE BIRD QUESTION. 451 



bv Dr. Fitch to be sometimes devoured to a considerable extent, whilst in the 

 larva state, by the black-capped yellow bird, or American goldfinch. The 

 bark-louse is still more minute, besides being protected by a scale which is 

 scarcely distinguishable from the bark of the tree. The curculio is also prob- 

 ably protected, to a great extent, from destruction by birds, by its resemblance 

 to the small knots and buds on the plum and peach trees. It is true, nature 

 has given to birds very sharp eyes to enable them to detect their insect prey, 

 but it is equally true that she has also endowed insects with the power of mim- 

 icry, apparently for the express purpose of protecting them from their feathered 

 enemies. And in point of fact, I believe birds have not been, known to fre- 

 quent, in increased numbers, the plum and peach orchards of the South, for 

 the purpose of feeding upon the curculios with which they are so abundantly 

 infested. Myriads of borers are undoubtedly destroyed by woodpeckers, 

 especially those which live under the bark, or in rotten wood; but the worst of 

 them, like the round-headed borer of the apple tree, penetrate so deeply into 

 the solid wood, at least iu the later stages of their existence, that even the 

 woodpeckers cannot reach them. With respect to the chinch bug and the 

 Colorado beetle, they seem to be absolutely repugnant to all kinds of birds, 

 with perhaps a few occasional exceptions, Avhich, however, are not very well 

 authenticated. 



It would be interesting, did time permit, to compare with the inefficacy of 

 birds in combating some of the more prolific and injurious species of insects, 

 the extensive destruction of many of these species by the natural enemies in 

 their own class, and especially by the parasitic insects. These creatures are so 

 minute that to all ordinary observation they may be said to be invisible, 

 and therefore their agency is almost unknown, except to professed entomol- 

 ogists, and even they have probably as yet formed no adequate conception of 

 the extent of their operations. But there are many cases on record where 

 some destructive insect has suddenly disappeared without obvious cause, and 

 upon examination every remnant of them is found to be infested by one or 

 more of these internal parasites. But these, also, have their preferences in the 

 selection of their foster-parents, and seem to be especially addicted to the larvae 

 of the Lepidoptera. Striking instances have been known of the wholesale 

 destruction of the army worm, the tent caterpillar of the forest, and the larvffi 

 of the tussock moth in this manner. But there are some of our most destruc- 

 tive insects, of which the chinch bug is a notorious example, which are almost 

 completely exempt from damage by natural enemies of any kind, and the only 

 sure remedy which is sometimes left to us in such cases is the final one of 

 abandoning for a time the crops upon which they chiefly subsist. 



Here, too, would be the proper place to introduce a consideration of a ques- 

 tion which has been sometimes raised, whether birds may not do a great deal 

 of harm by destroying indiscriminately the beneficial insects, both predaceous 

 and parasitic. The argument is this: that many of the insects destroyed by 

 birds are infested by internal parasites, often many in number, each one of 

 which, when arrived at maturity, would be instrumental in destroying many 

 more, and therefore that in devouring these infested individuals, birds destroy 

 many more of our friends than of our enemies. This, like many other plaus- 

 ible arguments, shows its own fallacy by proving too much. If birds do more 

 harm than good by destroying parasitized insects, then so do we, and we 

 should abstain from killing all kinds of noxious insects for the same reason. 

 This position assumes that the class of insects contains within itself a sufficient 



