ate aE ETS 
DAMAGE TO RANGE GRASSES BY THE ZUNI PRAIRIE DOG 13 
destruction of the range grasses over great areas is to be prevented, 
these campaigns must ‘be increased in scope and number. 
Careful attention to the plants eaten in the tall-grass and short- 
grass forage types at Coconino, Williams, and Seligman, Ariz., 
has shown conclusively that prairie dogs here consume only the 
plants eaten by cattle and do not touch plants which cattle find un- 
‘palatable. Hence these rodents compete directly with cattle for the 
usual forage plants of this region. 
Not only do the rodents eat the same grasses, but they take them 
in the same order of preference that cattle do. At Coconino, for 
example, both eat the grasses in the following order: Dropseed, 
wheat grass, blue grama. At Seligman both cattle and prairie dogs 
grazed the Russian thistle (Salsola pestifer) when it was young and 
tender, but when old and tough neither would touch it. Prairie 
dogs can graze the forage much more closely than cattle, and, there- 
fore, are able to subsist where cattle can not and are far more ce- 
structive to valuable range plants. 
As previously suggested, the prairie dog does much more damage 
to the range during seasons of drought than at other times. Whole- 
sale poisoning of the rodents may well increase the forage in certain 
instances sufficiently to permit the cattleman to carry his stock 
through the dry period without loss. 
So far as these experiments now indicate, the prairie dog does not 
possess a single beneficial food habit; nor is there any argument, so far 
as available facts or figures indicate, against its complete eradication 
on all grazing ranges. The data here presented show conclusively 
that the comparatively small expense of eradication is more than 
justified. 
In many overgrazed areas, apparently, total eradication of prairie 
dogs and reduction in the number of cattle per unit area will be 
necessary if the forage crop is to continue profitable. Almost anyone 
can realize the serious damage done when the forage plants are ut- 
terly destroyed and vast areas rendered worthless; but many stock- 
men do not properly appreciate the constant heavy losses to which 
they are subjected by prairie dogs through decreased carrying capac- 
ity of the range, even where the grass appears to be maintaining 
itself. 
SUMMARY AND CONCLUSIONS. 
To determine quantitatively the character of prairie-dog damage 
to the range in northern Arizona and the principal forage types 
affected, two sets of experimental inclosures have been established, 
one near Coconino, in the wheat-grass forage type; the other near 
Williams, in the blue-grama type. Three plots were selected i in each’: 
(1) One subject to cattle (or cattle and prairie-dog) grazing; (2) one 
to prairie-dog grazing only; and (3) one protected from. all grazing. 
Grasses from meter quadrats on the plots were measured, charted, 
clipped, and weighed each year. 
Results of four years’ experiments at. Coconino show that prairie 
dogs destroy 69 per cent of the wheat grass and 99 per cent of the 
dropseed, or 80 per cent of the total potential annual pr oduction of 
forage. Results of one year’s experiments at Williams show that the 
