10 BULLETIN 1227, U. S. DEPARTMENT OF AGRICULTURE 
around on barbed wire. Above the galvanized net wire were three 
barbed wires at 6 to 8 inch intervals. The south area (planned for 
a total protection tract) was inclosed with 6 barbed wires and with 
galvanized’ net wire, 1-inch mesh, to exclude prairie dogs. Installa- 
tion was by the Biological Survey and the Forest Service jointly. 
it’ seemed to be well-nigh impossible to confine prairie dogs in 
the inclosure successfully, even though an apron of galvanized net 
wire was later installed inside and buried in the ground in an at- 
tempt to prevent their escape; they either found some way to get 
out, perished from natural causes, or became the prey of predatory 
animals or birds. It was then concluded to try a different plan, and 
the north inclosure was retained as a total-protection plot instead 
of a prairie-dog inclosure, and by removing the galvanized net wire, 
the south plot was so arranged as to permit free grazing and coloniz- 
ing of prairie dogs from the outside, though cattle were excluded by 
the barbed wire as before. 
This arrangement, according to which no attempt was made to 
confine the prairie dogs, was found much more satisfactory than 
the previous one. Meter quadrats were installed on November 6, 
1919, one in each of the plots, and one outside of the fences. Addi- 
tional quadrats were measured off and typical quadrats were clipped 
for the first time on October 18, 1922, this being the first year when 
reliable and significant results could be obtained in this way. 
PROGRESS OF THE EXPERIMENT. 
The failure of earlier attempts to retain prairie dogs in their 
inclosure and to stop their invasion of the total-protection area pre- 
vented the obtaining of results of much value in regard to the effect 
of rodents on forage until the season of 1922, when (as observed 
during the month of October) contrasts were marked. The blue 
grama (Louteloua gracilis) (Pl. VI) showed many seeding heads 
in the total-protection area, though very few were noted in the 
prairie-dog plot or outside. Many clumps of a tall grass, bottle- 
brush squirrel-tail (Sztanion hystrix), and a few of sand dropseed 
(Sporobolus cryptandrus) were observed in the total-protection 
area, while neither grass was in evidence either in the prairie-dog 
plot or outside the fences. 
It is obvious that these grasses were enjoying far more favorable 
opportunities for seeding in the total-protection area than in the 
prairie-dog plot. The prairie dogs evidently not only destroyed an 
appreciable quantity, by weight and bulk, of the best forage plants, 
but also attacked them at their critical seeding period, thus having 
a markedly detrimental effect on their reproduction. The infesta- 
tion of prairie dogs in the plot appeared to be about the same 
as, Or in some cases much less than, the average infestation in 
the open country round about. It is felt, therefore, that the figures 
given are a conservative statement of actual destruction of this 
type of forage by prairie dogs under the prevailing conditions in the 
vicinity. 
