No. 21. PENNSYLVANIA STATE COLLEGE, 209 
as a rare breeder in favorable localities in Pennsylvania, but so far 
as my experience goes it is found here simply as a winter resident, 
arriving from more northern latitudes early in November and depart- 
ing in April. This species is of the greatest benefit to the farmer 
and fruit grower, as it subsists during its residence here almost 
wholly upon destructive rodents, especially mice. A colony of 
Short-eared Owls, if left unmolested, will in a short time destroy all 
the mice in a large meadow. Dr. Fisher has found as many as six 
wwice in the stomach of a single owl, and the writer has taken four 
mice from the stomach of one of these birds. Some few years ago 
when stuffed owl-heads were fashionable ornaments for ladies hats, 
luany of these owls were slain by hunters in the employ of milliners 
and taxidermists, on the farms of some of my acquaintances, who 
afterwards informed me they were convinced that the marked in- 
crease of field mice on their premises was due to the destruction of 
these and other birds of prey, such as hawks (Sparrow, Red-tailed, 
Red-shouldered and Rough-legged), which were killed by hunters 
for the bounty at that time allowed by this State. 
The stomach contents of thirty-five Short-eared Owls examined by 
the writer during the past ten years revealed chiefly field mice, a 
few birds (sparrows) and some insects, beetles and grasshoppers. 
These owls were all captured in Pennsylvania during the winter 
season. Two had remains of sparrows in their stomachs and three 
contained the insects above mentioned in conjunction with the hair 
and bones of small rodents; the remaining thirty owls had only mice 
or shrews in their stomachs. Dr. Fisher states that it is quite excep- 
tional for this owl to feed upon birds, and further adds that of 
ninety stomachs examined at the National Department of A gricul- 
ture but ten contained the remains of birds. 
“The following important evidence of the economic value of the 
Short-eared Owl is from the fourth edition of Yarrell’s British Birds 
(Vol. IV, p. 165.): ‘Undoubtedly, field mice, and especially those of 
the short-tailed group or voles, are their chief objects of prey, and 
when these animals increase in an extraordinary and unaccountable 
way, as they sometimes do, so as to become extremely mischievous, 
owls, particularly of this species, flock to devour them. Thus there 
are records of a ‘sore plague of strange mice’ in Kent and Essex in 
the year 1580 or 1581, and again in the county last mentioned in 
1648. In 1754 the same thing is said to have occurred at Hilgay, 
near Downham Market, in Norfolk, while within the present century 
the Forest of Dean, in Gloncestershire and some parts of Scotland 
have been similarly infested. In all these cases owls are menrioned 
as thronging to the spot and rendering the greatest service in extir- 
pating the pests. The like has also been observed in Scandinavia 
17 B. 
