AVES 



IQI 



more good than harm and should, therefore, for purely economic reasons 

 be protected. In a few cases the good and bad traits are so equally 

 balanced that it is difficult to decide upon the economic status of the 

 ,species; and in still fewer cases the bad traits clearly overbalance the 

 good ones and the species are rated as pests. 



Another way in which birds are of great benefit to agriculture, and 

 one that needs emphasizing more than the others, is in the destruction of 

 field mice and other rodent pests, to be discussed later. The birds that 

 do this valuable work are the various 

 species of hawks and owls. The 

 latter being nocturnal are more or 

 less free from the danger of man's 

 firearms; but the former are almost 

 universally considered, by farmers 

 and others to be pests, since some of 

 them, at times, do destroy young 

 poultry and beneficial birds. The 

 owls being nocturnal are especially 

 adapted to feed on rodents which 

 are also largely nocturnal in habits, 

 and with the possible exception of 

 the Great Horned Owl, they are all 

 considered to be beneficial birds. 



The Great Horned Owl, Bubo 

 mrginianus, Fig. 119, is a large 

 species, nearly 2 feet long, with 

 prominent ear-tufts that give the 

 appearance of horns; it lives in less 

 populous regions and destroys poul- 

 try and birds in considerable num- 

 bers, but often counterbalances this 

 damage by the destruction of rabbits 

 that, in many places, are a pest, as will be noted later. 



Fisher (143) found that, "Of 127 stomachs (of the owl) examined, 

 31 contained poultry or game birds; 8, other birds; 13, mice; 65, other 

 mammals; i, a scorpion; i, a fish; 10, insects; and 17 were empty." 

 It will be seen that of these stomachs only 39 contained birds while 78 



PIG. 119. Great horned owl, Bubo 

 virginianus. X%. 



