APPRAISAL OF THE VARIOUS SPECIES 343 



one of the many pellets examined. The principal foods of this owl are mice and shrews, the 

 latter being eaten more frequenth than by any of the other predators observed. Small birds 

 and insects were also taken to some extent. 



Fisher"" likewise found small mammals to be the chief food of this owl, although he re- 

 ported that in 100 stomachs poultry and game amounted to 4.5 per cent, mainly "half- 

 grown fowls which roost among trees and bushes". 



Snowy Owl 



The four specimens of this owl containing food are too few to indicate much regarding 

 its food habits. Gross'"', however, has reported the contents of 284 stomachs, 135 of which 

 were empty, collected in New England during the flight of 1926-27. He found over 75 

 per cent had fed on small mammals, especially the Norvvay rat. A wide variety of birds had 

 also been eaten including one grouse. 



Goshawk 



Although the number of specimens secured was small, analysis of their contents further 

 demonstrates the tendency of this hawk tf) prey heavily on birds. Grouse occurred in one 

 of 11 stomachs, pheasants in two and small birds in four, while small mammals had been 

 taken by five of the birds. 



Of all the ra|)tors of the Northeast the goshawk comes closest to meriting the name 

 "partridge hawk". Reporting on 243 examinations McAtee°" states "Grouse, chiefly ruffed 

 grouse, were di'lcrniiiii'd in 31 of the stomachs". Tie also found birds of one kind or 

 another in over lialf of the same group. Similarly in 538 stomachs from I'eimsylvania 153 

 or 28.5 per cent contained grouse and many others the remains of smaller birds, while 

 about half held the remains of small mammals, chiefly rabbits and squirrels"^. 



Cooper's Hawk 



Like the goshawk the Coo])er's hawk feeds extensively on other birds. It preys largely 

 on non-game species because they are more abundant and more within its capabilities. Yet 

 grouse are taken just as readily whenever a suitable opportunity presents itself. Mammals 

 had been eaten by onlv a little over a third of the s|)ecimens examined. Its preference for 

 birds has been corroborated many times by other workers. 



Of interest is the high proportion — nearly half — of the stomachs of this hawk which 

 have been empty. The same is also true of the next species, the sharp-shin. It suggests 

 that their rate of digestion ma\ be quite rapid. 



Sharp- shinned Hawk 



This hawk preys even more predominantly on birds than either of the two preceding. 

 Due to its small size, however, game species are seldom taken except as chicks. In the 

 specimens examined b\ the Investigation over 80 per cent of its food has been small birds, 

 the balance being rodents, chiefly mice. McAtee"' has reported a small variety of other 

 foods. The records reported bv May"' follow the same pattern. 



Red-tailed Hawk 



This hawk, so frequentlv seen wheeling in broad circles over field and pasture, is pri- 

 marily a mouser. Nearlv half of those examined had fed on these rodents, mainly the 

 field mouse, while shrews, ralibits and squirrels were also taken in considerable numbers. 



