IN REPLY REFER TO                                                  ADDRESS
ONLY THE 
CHIEF. BUREAU OF BIOLOGICAL SURVEY 
0 
Work                         UNITED STATES 
DEPARTMENT OF THE INTERIOR 
BUREAU OF BIOLOGICAL SURVEY 
WASHINGTON 
November 9, 1939 
Professor Aldo Leopold, 
Division of Wildlife -Lanaement, 
424 University Farm Place, 
Madis on, Wisconsin. 
Dear Mr. Leopold: 
Your letter of October 10 has been held for study by various 
Divisions affected in the Bureau. 
I am in agreement with your viewpoint that much of our cooperative 
research program is not based on as long-time research as necessary to 
round out all the facts needed for basing a game management program. 
However, at all of the Units, the very nature of their primary projects 
indicates a long-time approach; for example, the life history, ecology, 
and management of the Rocky Mountain mule deer is of necessity a long- 
titne program. For convenience, this is broken up into 30 or 40 phases, 
to which graduate students' work can be devoted. When all of these 
phases are brought together, the logical assumption is that we will 
have a fairly good picture of the status, limiting factors, and require-

ments of this species. I could list 25 or 30 other long-tine projects 
of similar nature. 
Your comments on the need for studying the ecology of rodents is 
of interest, but I feel that research on this would hardly come within 
the realm of cooperative wildlife mana-ement research work. In the 
first place, I doubt if we could convince the State game and conserva- 
tion commissions that such an expenditure of their funds would be justi-

fied. However, we have included this program under our general project 
of forest and ranile-wildlife relationships, in which a great deal of 
work is being done in California, Oregon, Washington, kinnesota, New 
England, and the South. Some of this work has been going on for more 
than 25 years, which evidence is found in publications put out by the 
Bureau and its cooperators. 
The intensive work done by E. E. Horn at the San Joaquin Experi- 
mental Range and Experiment Station is set up to answer many of the ques-

tions that you have raised. This work has been under way for about three

years. It is our hope that this will prove to be a guide in determining 
at what points rodents become destructive to range and under what condi-

tions they tend to accelerate erosion. We believe it is possible to set