
ESTIMATE OF THE PROPORTION OF THE 
PRE~SEASON WOOD DUCK POPULATION BAGGED 
The best estimates of recovery rates for the continental pre- 
season population are 7.7 percent for immatures and 5.5 percent for 
adults (as shown in table 5 and discussed above). These rates can 
be used with data from the Mail Questionnaire Survey to estimate the 
proportion of the pre-season population that was bagged. The Mail 
Questionnaire Survey indicated that 49 percent of the wood duck bands 
taken are reported (Geis and Atwood, 1961). When wood duck recovery 
rates are adjusted to include unreported bands, it is estimated that 
15.7 percent of the immatures and 11.2 percent of the adults are 
bagged each year (hunting kill rate). If there is a crippling loss 
equal to 25 percent of the birds bagged, the kill estimate becomes 
19.6 percent for immatures and 14.0 percent for adults. It is 
reasonable to assume that annual rates of mortality from all causes 
are at least 50 percent for immatures and at least 40 percent for 
adults. If this is true, then hunting would account for less than 
one-half of the total mortality. It should be emphasized that this 
estimate is only a rough approximation. However, it suggests that 
hunting pressure might be less important to the continental wood duck 
population than it is to the mallard (Smith and Geis,1961) or the 
canvasback (Geis, 1960). This does not preclude the possibility that 
hunting is locally important. For example, it was shown above that 
recovery rates from wood ducks banded in northern States were sub- 
stantially higher than those from more southern banding areas. 
. PRE-SEASON POPULATION ESTIMATES 
Using the hunting kill rates derived in the previous section 
(15.7 percent for immatures and 11.2 percentfor adults), it is possible 
to estimate the size of the wood duck population before the hunting 
season. The population estimate is made by dividing the hunting kill 
rates of each age group into the estimate of the number of birds killed 
in each age group. The estimate of the total number of birds killed 
(266,873) is taken from the results of the Mail Questionnaire Survey 
(Atwood and Wells, 1961 a,b). Segregation of the kill estimate into 
‘age groups is based on the weighted age ratio (2.1) in the portion 
of the hunting kill examined by the Wing Collection Survey (Geis and 
Carney, 1961). Estimates of the pre-season population size and age 
ratio may be made from the following relationships: 
l. Ki/Ka = Piki/PaRa or, Ki = PiRi and Ka = PaRa 
Ki 
Ri/Ra 
- Ki/Ka 
3. Ri/Ra Kicks 
4, P= Pi + Pa = Ki/Ri + Ka/Ra 
2. Pi/Pa = 
ay 
6 
