Vol. 23, No. 10 
Page 4 
Possibly Deer 233 followed small drainage ditches that course through the 
area. These ditches offer little cover but would aid direction finding for at 
least part of the journey. 
The best explanation we have for the timing of this fall movement is that 
it was triggered by secretions of the endocrine system, possibly gonadotrophic 
hormones from the pituitary gland. These hormones are produced in females in 
response to the shortening days and preparatory to breeding in the fall. 
On 7 October, Deer 233 repeated the movement she made in the spring and 
returned to her summer range (Table 3)* We see no ecological advantage to the 
deer in this movement and offer no explanation for it. Future observations may 
provide more insight into the controls of these movements. 
Table 3* Characteristics of spring and fall movements of an adult, female 
white-tailed deer (Deer 233) and a description of some environmental conditions 
on the possible dates of movement. Weather data obtained from the Urbana station. 
Date 
Displacement 
Temperature 
Wi nd 
Sky- 
Lunar- 
Phase 
Mi 
Km 
Direc- 
t i on 
High 
Low 
Mean 
Speed 
(mph) 
Direc¬ 
ti on 
4/25 
12.2 
19-7 
SE 
58 
34 
46 
3.2 
ME 
Clr 
Full-5 
4/26 
12.2 
19-7 
SE 
61 
37 
49 
6.8 
N 
Cl r 
Full-4 
9/27 
12.2 
19.7 
NW 
70 
40 
55 
4.0 
SW 
PC 
Ful1+3 
9/28 
12.2 
19-7 
NW 
78 
45 
62 
2.0 
SE 
Clr 
Ful1+4 
10/7 
12.2 
19.7 
SE 
75 
46 
61 
4.5 
SW 
Clr 
New- 1 
■^Clr = clear, PC = partly cloudy 
■^Lunar phase given as the number of days before (-) or after (+) full or 
new moon. 
Cooperative Waterfowl Research - W-88-R F. C. Bellrose, 
S. P. Havera, 
G. A. Perkins, 
H. K. Archer 
Illinois is 330 miles long and has such diversified habitat as tamarack bogs 
in the north and cypress swamps in the south. Because it extends over such a 
range of latitude, different regions of the state are subject to a diverse 
chronology in the arrival and departure of waterfowl. A variety of wetlands also 
influences the distribution of waterfowl within Illinois. 
£ Illinois is subject to dramatic climatic and weather changes between seasons 
and years not only in temperature, but also in precipitation, snowfall, and 
