CLASS AVES 629 



poultry, and (3) the golden eagle, which is highly beneficial in 

 certain localities because of the noxious rodents it destroys. 

 The Cooper's hawk (Fig. 495) is the real " chicken hawk "; its 

 food is made up largely of poultry, pigeons, and wild birds, but 

 also includes the harmful English sparrows. 



The beneficial qualities of birds are well shown by Dr. S. D. 

 Judd * from a seven years' study of conditions on a small farm 

 near Marshall Hall, Maryland. Modern methods of investiga- 

 tion led Dr. Judd to the following conclusions :- 



" At Marshall Hall the English sparrow, the sharp-shinned 

 and Cooper hawks, and the great horned owl are, as everywhere, 

 inimical to the farmers' interests and should be killed at every 

 opportunity. The sapsucker punctures orchard trees exten- 

 sively and should be shot. The study of the crow is unfavorable 

 in results so far as these particular farms are concerned, partly 

 because of special conditions. Its work in removing carrion 

 and destroying insects is serviceable, but it does so much damage 

 to game, poultry, fruit, and grain that it more than counter- 

 balances this good and should be reduced in numbers. The crow 

 blackbird appears to be purely beneficial to these farms during 

 the breeding season and feeds extensively on weed seed during 

 migration, but at the latter time it is very injurious to grain. 

 More detailed observations are necessary to determine its proper 

 status at Marshall Hall. 



" The remaining species probably do more good than harm, and 

 except under unusual conditions should receive encouragement 

 by the owners of the farms. Certain species, such as flycatchers, 

 swallows, and warblers, prey to some extent upon useful para- 

 sitic insects, but, on the whole, the habits of these insectivorous 

 birds are productive of considerable good. Together with the 

 vireos, cuckoos, and woodpeckers (exclusive of the sapsuckers), 

 they are the most valuable conservators of foliage on the farms. 

 The quail, meadow-lark, orchard oriole, mocking-bird, house wren, 



1 Bulletin No. 17 of the Division of the Biological Survey of the United States 

 Department of Agriculture. 



