Figure 2. Trends in Breeding-population Indexes 
by Management Units, 1953-1961 
70 
oo ®, 
= 60 CENTRAL ™~, 
5 om, ~ 
el ad 
= 50 
E 
H 
3 40 
A= oo 
5 30 
3 WESTERN 
3 ' 
a. | en rs NE ee een ON oe ene 
a | 
3 10 EASTERN 
% 
@ 
ie 
4 

1953 1954 1955 1956 1957 1958 1959 1960 1961 
