SUPPRESSION OF RODENTS 187 
ticeable that when white weasel-skins are 
high-priced, and, consequently, many of these 
animals are trapped in winter, the following 
season will be one of excessive mischief by all 
the smaller rodents. 
L. C. Cummins, of Riverside, Cal., writing to 
the Biological Survey, February 12, 1892, says: 
At one nursery we were bothered with gophers; all 
at. once the gopher became scarce and from one to five 
weasels could be seen nearly every day running 
through the nursery stock and over an adjoining hill. 
They completely drove away and killed all the 
gophers. 
Useful aid by birds of prey. A similar ac- 
count might be made of the birds—not only 
birds of prey, of which the owls and the marsh- 
hawk are to be put foremost, but shrikes 
(butcher-birds), crows, jays, roadrunners, gulls 
and several of the heron tribe. Bitterns, egrets, 
cranes and the like, search steadily for mead- 
ow-mice. In California the great blue heron is 
protected on many ranches in realization of 
valuable service. A letter to The Pacific Rural 
Press, Oct. 23, 1897, from W. M. Bistoe, re- 
lated that a neighbor found barn-owls had 
