BIRD ENEMIES OF THE CODLING MOTH. 245 



ignicapillus) f one of the babblers (Pomatorkinus super ciliosus) ? 

 the white-eye (Zosterops ccerulescens} , 3 and the white-throated tree- 

 creeper (Climacteris leucophcea) , 4 of Australia. Woodpeckers and 

 sparrows are said to share in the work in Europe. 



With three exceptions these birds belong to the same families as 

 native species which we know devour the codling moth. These fam- 

 ilies are the creepers (Certhiidae), nuthatches (Sittidse), titmice 

 (Parida?), and kinglets (Sylviidae). The United States already has 

 a sufficient number of species of these families, besides numerous 

 members of other families, which, if properly protected and encour- 

 aged, will probably destroy more codling moths than foreign species. 

 To favor the increase and efficiency of our own useful species is not 

 only far more profitable than to introduce foreign ones, but avoids 

 the danger, acknowledged by all authorities as great, of opening 

 our doors to a bird that in its new home may become obnoxious. It 

 is a well-known fact that a very large number of our crop pests, 

 both plant and animal, are imported. Furthermore, it is clear that 

 the fundamental idea underlying proposals for introducing bird 

 enemies of the codling moth is false. This idea is that each pest has 

 some specific enemy or set of enemies which, if introduced, will 

 control it to such a degree that the usual combative measures like 

 spraying can be abandoned. This is a most alluring theory, but it is 

 not borne out by practical experience. Birds exert a constant re- 

 pressive influence on the number of insects, but those who expect 

 either native or introduced birds to control a widespread insect pest 

 to the degree necessary for the commercial success of the crop at- 

 tacked will be disappointed. 



SUMMARY. 



Birds are recognized as the most effective natural enemies of the 

 codling moth. In some localities they destroy from 66 to 85 per cent of 

 the hibernating larva?, and their work in large measure accounts for 

 the small spring broods of the insect. This annual reduction in 

 numbers of the pest is a very valuable factor in its control. 



Thirty-six species of birds are known to prey upon the codling 

 moth in the United States. These species belong to 13 families, of 

 which the most important, so far as number of species on the list is 

 concerned, are the woodpeckers, titmice, and sparrows. Especially 

 valuable species are the downy woodpecker, Bullock oriole, black- 

 headed grosbeak, and bush tit. 



1 Bos, J. Ritzema. Tierische Schadlinge und Niitzlinge, p. 527, Berlin, 1891. 



2 Curnow, S. II. Journ. Agr. S. Australia, p. 20, Aug., 1909. 

 8 Emu, VII, pt. 1, p. 36, July, 1908. 



4 Journ. Agr. Victoria, IX, pt. 8, p. 552, Aug., 1911. 



