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UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1227 
Washington, D. C. August 10, 1924 
DAMAGE TO RANGE GRASSES BY THE ZUNI PRAIRIE DOG. 
By WaAtterR P. Taytor, Biologist, Division of Biological Investigations, Bureau 
of Biological Survey, and J. VY. G. LOFTFIELD, Assistant Ecologist, Carnegie 
Institution of Washington. 
CONTENTS. 
Page Page 
LEVEL CO 0) 0 toi eS Sa ae eR ee ss 1 | Some grazing relations of prairie dogs__ 11 
Meredatiom alrected: |: s72— 2 6 aes 8 | Summary and conclusions_____-— Cott £2 83 
The Coconino experiment_________~-~- 45 bc IAGORRe Re selbed, s6 ee Ro 15 
The Williams experiment______-____-~ 9 
INTRODUCTION. 
That native rodents cause heavy losses both in cultivated crops and 
in forage plants on the pasture and range has long been recognized. 
Indeed, after a careful calculation, the Biological Survey has con- 
servatively estimated the losses in crops in the United States at 
$150,000,000 annually, and in forage plants on the open range at a 
like sum—a total annual loss of $300,000,000 from this source (Nel- 
son, 1918, p. 2, and 1919, p. 5; Taylor, 1920, p. 283; Bell, 1921, p. 
493).1 Determinations under controlled conditions of the actual 
damage done by rodents, either in cultivated crops or on the open 
range, are, however, almost wholly lacking. The first paper dealing 
in a precise manner with such damage is that of W. T. Shaw (1920) 
who made a determination of the destruction of wheat by the Colum- 
bian ground squirrel (C7tellus columbianus Ord) in eastern Washing- 
ton. No comprehensive published results dealing quantitatively with 
rodent damage on the open range have been seen. 
The difficulties in the way of this kind of experiment, while not 
small, are by no means insurmountable; and it is believed that esti- 
1 Literature references and numbers in parenthesis refer to citations in ‘“ Literature 
Cited,” page 15 
Notn.—This bulletin is a report on a cooperative undertaking between the Biological 
Survey, the Carnegie Institution of Washington, the Forest Service, and the Arizona Agri- 
eultural Experiment Station to ascertain quantitatively the destructiveness of prairie dogs 
to stock ranges. It is for the information of stockmen and others interested in the 
control of rodent pests of the range, 
71516°— 24 
