J. B. HARKIN,                                             NATIONAL PARKS

      COMMISSIONER                                        MIGRATORY BIRDS
CONVENTION ACT 
                                                          HISTORIC SITES

 
                       DEPARTMENT -OF THE INTERIOR 
 
                           NATIONAL PARKS OF CANADA 
                                   OTTAWA 
 IN YOU REPLY REFE To FILEPERSONAL.         June 16,1930. 
 
 
 
 
 
                Dear Leopold,- 
 
                                I was very much interested ih your 
                beginning of a summary of drinking habits of game 
                birds and mammals. Unfortunately, I am afraid that 
                I have not much to add. There is a good deal of 
                valuable information hidden in private note books, 
                however, and I think that you might get good infor- 
                mnation by encouraging observers to record what they 
                have seen in places where it will be available to 
                subsequent workers in the same field. To my mind 
                there is always the danger of getting erroneous in- 
                formation by sending out a simple questionnaire. The 
                questions sometimes have the effect of being leading 
                questions and of influencing the answers. This ob- 
                jection does not arise where the obseiver records 
                the things that he sees without any definite ques- 
                tions before him. 
 
                                Perhaps it would help you to circul- 
                arize such papers as "The Auk," The Journal of
Mam- 
                malogy," Eind the Canadian Field-Naturalist " and
try 
                to encourage observers to place on record facts re- 
                lating to the water requirements of game. 
 
                                With kind regards, I remain 
 
Aldo Leopold., Esq.,                Yours very truly, 
 
    In Charge, Game Survey, 
 
       421 Chemistry Building, 
 
 
Madison, Wisconsin, U.S.A.