430 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



Parker and associates found wild birds to be the most beneficial 

 check upon the pale western cutworm {Porosagrotis orthogonia) in 

 Montana. In Texas the boat-tailed grackle, locally called jackdaw, 

 has several times been observed to clean up infestations of the cab- 

 baj^e loopcr {Autographa hrassicae). The fall army worm has 

 been extirpated from a peanut field in Florida by blackbirds, and 

 from a millet field in Georgia by English sparrows. There are 

 recorded instances of control of the common army worm in Canada 

 and New York, and of local extirpation in Pennsylvania and Min- 

 nesota. Dr. Townend Glover reports that " a southern planter 

 once stated to me that the cotton boll worm, which was destroying 

 his cotton crop, had entirely disappeared after the visit of an im- 

 mense flock of blackbirds, which, after devouring the worms, imme- 

 diately left the neighborhood." ^^ 



The oak caterpillars {Dataim) are large and conspicuously col- 

 ored and have threatening actions, but all these characteristics com- 

 bined do not prevent attacks by birds. In the District of Columbia, 

 Mr, Robert Ridgway observed cuckoos feeding so persistently on 

 a colony of Datana integerrima on black walnut that within a week 

 it was absolutely exterminated. The destructive Zimmerman pine 

 moth {Pinipestis) of the same family has serious bird enemies, and 

 ;Mr. Josef Brunner reports that in the Rocky Mountain region the 

 hairy woodpecker is unquestionably the most efficient natural force 

 restraining the species. 



Only a few species of birds have been observed feeding on the 

 European corn borer, but among them the woodpeckers seem to do 

 considerable good in some cases. Messrs. G. J. Spencer and H. G. 

 Crawford, reporting on their studies in Ontario, state that " the 

 downy and hairy woodpeckers have frequently been seen digging 

 the borers out of the stalks and stubbles in the field. In one field 

 these birds were computed to have taken GO per cent of the borers."-^ 



The tussock moth caterpillar is generally supposed to be too hairy 

 for birds, but this is another strained assumption. When they are 

 common in Washington, nearly every robin seen carrying food to 

 its young shows a telltale white fluff at the end of its bill. Dr. J. M. 

 Swaine and Mr. Alan G. Dustan report birds to be important 

 enemies of the tussock moth in Canada, Mr. Dustan especially 

 having made some interesting observations along this line. He 

 found that birds and ants are responsible for holding the insect 

 at par in forests. When he exposed larva? to birds, the supply dis- 

 appeared regularly and he credits birds with destroying half of the 



so Rep. U. S. Commr. Agr. (1865) 1866, p. 42. 

 " Hull. 295, Ont. Dept. Agr., March, 192:{, p. 7. 



