SHORT-EARED OWL 179 



bark" and that of the young like the sound of ' 'escaping steam turned 

 on and off suddenly but lasting about three seconds." 



Field marks. — As the short-eared owl skims the marshes and fields 

 like a harrier, it might be mistaken for a marsh hawk, but the much 

 shorter tail and the large round owl head, as well as the absence of 

 white on the rump, ma^e its identification easy. The small "horns" 

 or "ear-tufts" can not be seen in flight and only rarely when the bird 

 is perched. They are so short that they are concealed when the bird 

 is alarmed or excited and erects the feathers of the head. The light 

 under parts of the bird and the small oblong black patches at the base 

 of the primaries seen from below are good field marks. It is about 

 the size of the broad-winged hawk from which it is at once distin- 

 guished by its round head. A patch of creamy brown on the upper 

 surface of the open wing is also distinctive. 



Winter. — As small rodents are the favorite food of this owl, it 

 generally migrates south to grassy and weedy regions where there is 

 little or no snow. In such favorable localities they sometimes collect 

 in considerable numbers. Harris (1919) describes such gatherings in 

 flocks of 8 to 50 in the prairies close to buildings in Kansas City, 

 and Tyler (1913), in the Fresno district of California, estimated as 

 many as 200 of these owls hunting over stubblefields at sunset one 

 December afternoon. 



Frank L. Farley contributes the following note: "In the fall of 



1931, when engaged in threshing their grain, farmers in central 

 Alberta noted an unprecedented number of mice in the fields. Later, 

 when winter set in and threshing operations were halted on account 

 of deep snow and extreme cold, it was discovered that the grain 

 shocks in the fields were infested with the rodents, as many as a dozen 

 of the destructive little animals having taken up their winter quarters 

 under a single shock. In October and November, unusual numbers 

 of short-eared owls were observed patrolling the fields, hunting for 

 mice, and later their numbers were augmented by the arrival of 

 thousands of northern-bred birds. On December 31, 1931, H. A. 

 MacGregor and I drove 25 miles by automobile, south of Camrose 

 through the Duhamel country, and saw 24 of these owls. All were 

 hunting in, or adjacent to, fields of shocked grain. John W. Russell 

 recorded in 16 days, between November 26, 1931, and February 5, 



1932, 116 owls, this being at the rate of 7.25 a day. The number of 

 mice that this vast army of owls destroyed must have reached enor- 

 mous proportions, and the birds may have prevented what otherwise 

 would have resulted in a serious plague. An invaluable service was 

 rendered at a time of emergency, and at no cost whatever to the 

 people." 



The short-eared owl is an interesting and beneficial bird. May it 

 long survive ! 



