CHECKS UPON INCREASE OF USEFUL BIRDS. 369 



of both Crow and ^'^.y have been pubhshed elsewliere.^ The 

 American Crow (Corrus americanu>t) Is a most deadly enemy 

 to birds from the size of the Chipping Sparrow to that of the 

 Night Heron, Ruffed Grouse, and Black Duck, for it contin- 

 ually steals the eggs and young of such birds and poultry. 

 The evidence on this point is so con- 

 vincing and voluminous that it is jjli< 



4mh>i 



^i}% 



impossible to avoid this conclu- 

 sion, although it is quite prob- 

 able that only certain 

 individual Crows are 

 the criminals. Crows 

 not only destroy eggs anc 

 young birds, but they ha\ 

 been known to band together 

 to hunt down and kill adult 

 as large as the Kuffed (Tr( 



The well-known Blue Jay 

 {Cyanocitta crista/a) is destructive 

 to the eofo-s of the smaller l)irds, 

 whose nests it robs systematically, 

 and it has frecjucntly been seen to 

 kill the young. The Rol)in and othei' 

 larger birds will drive the Jay away Fig. 155. -Blue. lay.oue- 



„ , . . ^ ' lialf natural size. 



from their nests, but it often succeeds 



in robbing them by stealth. Vireos, Warblers, and Spar- 

 rows it regards very little, and plunders their nests without 

 noticing their agonized cries. Jays and Crows toijether 

 sometimes make it very difficult for other birds to raise any 

 young. It would not be advisal)le to exterminate the Crow, 

 for it has many useful habits ; but it should not be allowed 

 to increase at the expense of the smaller birds. Crows are 

 valuable as grasshopper killers, and they are destructive to 

 the gipsy moth. Jays eat the eggs of the tent caterpillar 

 moth, and the larvii? of the gipsy moth and other haiiy cater- 



' See The Crow in Massachusetts, Animal Report of tlie Massachusetts State 

 Board of Agriculture, 1896, pp. 285-289; Two Years with the Birds on a Farm, 

 P)id., 1902, pp. 147-149; and The Decrease of Certain Birds, IbuL. 1904, pp. 498- 

 502. 



