Prof. Aldo Leopold 
If your picture turns out well, I would appreciate having a copy. 
I hope that you and Mr. Pough have a pleasant and profitable day 
in the field at Prairie du Sac. In my opinion the following 
territories (see map, pp. 394-395, of Bulletin #201) show the 
Oost promise for "proofing": #13 (the little piece of the #5 and

#13 combination that lies north of the road on which Gastrow's 
farm house is situated), #14 (the lethal), #20, #29, and possibly 
#11 and certain parts of the combinations of #6, 12, #15, #16, and 
#54 and #4, #17, #18, and #19. 
I doubt if you would find it very profitable to question Gastrow 
closely on suggested improvements. For an unlettered man, I feel 
that he knows a great deal but I feel also that his chief strength 
lies in knowing where everything is, his ability to made good 
counts, and his loyalty and interest. He would probably become 
hopelessly swamped in any discussion of population vulnerability 
or any other ecological complexity. In fact, until I had sent 
him a copy of Bulletin #201 last summer, I deliberately aimed to 
keep him in the dark on that subject; I wanted to take no un- 
necessary chances on the reliability of his census figures being 
lessened by any unconscious desire on his part to prove" any- 
Mr. Pough spent a day with me enroute to Pierre. I am very much 
encouraged by what the Audubon Society is undertaking and think 
that their program is one of real promise. 
PL iflBB                     Paul L. Errington 
Res. Asst. Professor