EASTERN SCREECH OWL 253 



a screech owl swooped down twice and caught them; once it came with- 

 in 3 or 4 feet of my hands." 



Mr. Forbush (1927) says: "Professor Aughey dissected 8 of these 

 owls in Nebraska during locust invasions and in their stomachs found 

 219 locusts, 2757 other insects, 2 mice and 1 small bird. The one that 

 had eaten the bird contained also 32 locusts and 8 other insects." 



In addition to mammals, birds, and insects, the screech owl has been 

 known to eat snakes, lizards, frogs, toads, various fishes, crayfishes, 

 snails, salamanders, spiders, scorpions, millipeds, and earthworms. 

 M. A. Frazar (1877) found in a screech owl's roosting hole sixteen 

 horned pouts, four of which were alive; all the ponds in the vicinity 

 were under 2 feet of snow and ice, but in one pond, fully a mile away, 

 a hole had been cut in the ice by fishermen, where he inferred that the 

 owl had caught the fish ; this involved a total flight of 32 miles for the 16 

 fish. 



With such an extensive and varied bill of fare, it is difficult to arrive 

 at any general conclusion as to the economic status of this owl. 

 It depends largely on its environment and the most readily available 

 food supply, for this owl evidently is satisfied with what animal food it 

 can most easily obtain. Where mice, rats, and and other small mam- 

 mals are abundant, it apparently prefers them; in destroying them and 

 in eating so many locusts, cutworms, and other noxious insects, it is 

 decidedly beneficial. There are several cases on record, to its credit, 

 where it has been useful in keeping in check, or driving away, an over- 

 abundance of English sparrows, which had become a nuisance in barns, 

 hangars, and vine-clad houses. 



But in a bird sanctuary a screech owl is an unwelcome guest. 

 Miss Sherman (1911) found that her screech owls killed a great many 

 small birds, especially juncos and song sparrows; all the latter dis- 

 appeared in time; her verdict on the owls was that "their ravages were 

 so great that it was decided if we desired a little bird paradise where all 

 good birds were welcome through the summer time there Screech 

 Owls could not be encouraged to remain." 



Dr. Allen (1924) draws the following conclusions from his studies: 



A census of the birds nesting in the sanctuary in 1923 showed a slight increase 

 in the total number rather than a decrease, though all species exterminated in 

 1922 failed to reappear in 1923. * * * 



There can be little doubt that the number of insects and small mammals 

 destroyed by this pair of Owls could never compensate for the destruction of one 

 tenth of the insectivorous birds eaten by the young. Though the Owls might 

 spend the rest of the year feeding entirely upon insects and meadow mice, they 

 could not possibly consume the equivalent of what would have been eaten by the 98 

 birds destroyed during the short space of eight weeks. 



From the data here presented it seems evident that the Screech Owl is a powerful 

 factor in maintaining the balance of nature but, from the standpoint of increasing 

 insectivorous birds, he is an equally powerful menace. 



