estimates are contemplated for that 
year. 
Mallard age ratios 
Age ratio of mallards killed in the 
Atlantic Flyway during the 1963-64 hunting 
season, showed a slight increase but is 
still slibstantially lower than the ratio 
obtained in 1960-61. The birds killed in 
Pennsylvania and other more northern 
States in the Atlantic Flyway showed a 
higher ratio of immature to adult (2. 53) 
than did the States south of Pennsylvania 
(1.25). 
The ratio of immature to adult mal¬ 
lards killed in the Mississippi Flyway 
during the 1963 hunting season (1. 30) 
showed a slight decline from the ratio 
observed in 1962 (1.40), particularly in 
the northern part of the Flyway. Age 
ratios in the southern half of the Flyway 
tended to rise slightly or remained rel¬ 
atively unchanged. 
Although steadily increasing since 
1961, the Central Flyway mallard age 
ratio was still the lowest in the Nation for 
the third consecutive year. The observed 
ratio in the kill was 0. 69 in 1961, com¬ 
pared with 0. 94 in 1962 and 1. 03 in 1963. 
In the Central Flyway States of Mon¬ 
tana, Wyoming, and Colorado, the wing 
survey data were segregated by counties 
east and west of the Continental Divide 
because those counties east of the Con¬ 
tinental Divide were subject to regula¬ 
tions of the Central Flyway, and those 
counties west of the Divide were governed 
by Pacific Flyway regulations. New 
Mexico was not divided in this manner be¬ 
cause the Continental Divide does not 
follow county lines. 
In Montana the age ratio in 1963 was 
much higher west of the Divide than east. 
Conversely, in Wyoming and Colorado 
mallard age ratios west of the Divide 
were relatively low and only slightly 
higher than east of the Divide. 
The mallard age ratio in the Pacific 
Flyway kill increased from 1. 25 im¬ 
matures to adult in 1962 to 1. 62 in 1963. 
This represents a gain of 30 percent Over 
1962, 
In the 3 years that wing collection sur¬ 
vey data have been available for all Fly- 
ways, the continental weighted age ratio 
of mallards has shown a steady increase 
from 1.05 immatures to adult in 1961 to 
1.36 immatures to adult in 1963 (table 
D-20). 
In order to determine the age compo¬ 
sition of the preseason population, it is 
necessary to correct the age ratios 
observed in the kill for the greater vul¬ 
nerability of immatures to hunting. The 
preseason banding data presented in Ad¬ 
ministrative Report 46 were examined to 
determine the extent to which recovery 
rates from immatures taken in the 
United States exceeded recovery rates 
from adults. The recovery rates from 
each area were weighted in approximate 
proportion to the importance of the size 
of the population it represents and the 
Flyway or Flyways to which its re¬ 
coveries relate. Although this approach 
should yield average relative recovery 
rates that are more representative than 
the unweighted averages presented in 
past reports, it places a great deal of 
weight on the meager and uncomparable 
preseason bandings in the Prairie Prov¬ 
inces of Canada. In fact, preseason 
bandings in Canada in 1962 were so few 
that it was necessary to assume that the 
data from 1963 also reflected the char¬ 
acteristics of the kill in 1962. Thus, by 
giving each banding station equal weight, 
as has been necessary in the past owing 
to a lack of information from Canada, 
estimates of relative recovery rates may 
be biased. The 1963 preseason bandings 
in Canada for the first time were suf¬ 
ficient to illustrate the advisability of 
recognizing that mallards banded in 
Canada have different kill rate character¬ 
istics than those banded in the United 
States. 
A study is in progress to develop ap¬ 
propriate weighting prdcedures, but the 
results are not yet available. A pre¬ 
liminary summation of the data indicates 
that in 1962 immatures were about 1.4 
times more likely to be shot than adults 
and in 1963 they were 1. 3 times more 
likely to be taken. It is believed that the 
33 
