DEPARTMENT OF                                      BOARD OF NATURAL RESOURCES
REGISTRATION AND EDUCATION                                 AND CONSERVATION
FRANK G. THOMPSON. DIRECTOR                             FRANK G. THOMPSON. CHAIRMAN
SPRINGFIELD                                       BIOLOGY  WILLIAM TRELEASE
FORESTRY  *  -  EZRAJ.KRAUS
GEOLOGY  *  NORMAN L. BOWEN
ENGINEERING  *  LOUIS R. HOWSON
CHEMISTRY  .   -  ROGER ADAMS
STATE OF ILLINOIS       UNIVERSITY OF ILLINOIS-
DWIGHT H. GREEN, GOVERNOR    PRESIDENT. ARTHUR C. WILLARD
STATE NATURAL HISTORY SURVEY DIVISION
THEODORE H. FRISON, CHIEF
URBANA
August 4, 1945
Professor Aldo Leopold
Department of Wildlife Management
424 University Farm Place
Madison 5, Wisconsin
Dear Aldo:
Maybe I am talking a little early in the
season. However, the temperature late hatch idea
seems to be working out very well this year. We
had cool weather until July 11 or 12, and for the
fiht time since I have been checking on pheasant
broods, there are late June and early July broods
all over the place. It is not quite time for the
younger broods to show up yet, but we have late
broods, - and large ones, 8,9 and 10.
I don't know just how much the experimental
work will be worth. It looks to me as though high
incubating temperature is the answer, but I will
know more about it when I get the records from the
game farms together for past years. That is,I
believe temperature is the major factor. However,
Mt. Vernon is over 200 miles south of of Yorkville,
and I understand that the Mt. 'ernon birds always start
to lay about 2 weeks earlier than those at Yorkville,
but both end laying about the same time. Some of
the clutches in the pens at Mt. Vernon had only a
couple of e.'-gs, which may iot be significant, when
I examined nests in the pens there in mid July.
The fertility of late eggs was practically
the same at both game farms this year,and I got the
impression this is usually true. I intend to check the
past records.
Thisolatto-let you know how things look at
mid-season.
Si rely yours,
cc Wm. Elder            Ralph E. Yeatter
Game Specialist