OWLS AND FIELD MICE. 47 



The Reverend Doctor Jackel, of Windsheim, Bavaria, collected and 

 examined a total of 0,512 pellets of the barn owl. In them he identi- 

 fied skulls of 5,210 shrews and 14,790 rodents, of which 9,046 were 

 Microtus. Doctor Rorig more recently examined 121 pellets of barn 

 owl and in them identified 291 voles, 68 true mice, 35 shrews, and 13 

 sparrows, 6 a result more in harmony with Doctor Fisher's tables. 



John Watson calculates that each pair of owls of this species while 

 feeding their young capture at least 40 mice per day. Once he found 

 no fewer than 17 recently killed field mice on the side of a barn owl's 

 nest which contained 5 young owls. c The late Edward Newman 

 stated that every owl of this species is worth £5 per year to the British 

 nation/* 



The long-eared owl (Asio wilsonianus) is distributed throughout 

 temperate North America, except the treeless plains. It is a constant 

 resident over most of its range, and its usefulness in the destruction of 

 mice continues throughout the year. Of the 107 stomachs examined 

 by Doctor Fisher, 1 contained a quail; 15, other birds; 84, mice; 5, 

 other mammals ; 1, insects; and 15 were empty. Of the 84 containing 

 mice, 46 contained specimens positively identified as meadow and 

 pine mice. About 50 pellets cast up by long-eared owls contained 

 176 skulls, representing 93 meadow mice, 19 pine mice, 23 other mice, 

 26 shrews, and 13 small birds. 



The long-eared owl (Asio oius) of the Old World has a similar 

 record. Doctor Rorig made 108 stomach examinations of this species. 

 In the stomachs he identified 20 small birds, 1 weasel, 2 bats, 18 

 shrews, 29 true mice, 14 bank voles (Evotomys) , and 365 field mice 

 (Microtus). Nine stomachs contained insects. Eighty-four per cent 

 of the birds had eaten mice. A single stomach contained 12 field 

 mice. 



In 142 pellets of A. otus examined by Doctor Altum, he found 3 

 small birds, 2 shrews, 14 true mice, 12 bank voles, and 259 voles ( 1 M. 

 amphibius, 65 M. agrestis, and 193 M. arvalis. 6 Doctor Rorig ex- 

 amined 1,053 pellets of long-eared owl and found remains of 14 small 

 birds, 1 frog, 2 moles, 29 shrews, 22 true mice, 15 bank voles, and 

 1,764 voles. Selby found 5 mice in a single stomach of this species. 



The short-eared owl (Asio accipitrinus) is probably the greatest 

 enemy of field mice. It figures in many historical accounts of vole 

 plagues in England and on the Continent. Holinshed's Chronicle 

 closes the account of voles in Danesey Hundred, of the county of 



o Zoologische Garten, vol. 15, p. 469, 1874. 



&Arb. Biol. Abteiiung fur Land- und Forstwirtscbaft, IV Band, 1 Heft, 

 pp. 102-104, 1903. 



c Qrnitbology in Relation to Agriculture and Horticulture, p. 12, London, 1893, 

 d Hardwicke's Science Gossip, vol. 29, pp. 89-90, 1893. 

 « Journal fur Ornitbplogie, vol. 12, pp. 429-434, 1864. 



