
Atwood, E. L. Validity of mail survey data on bagged waterfowl. 
Journal of Wildlife Management, 20(1): 1-16. January 1956, 
Atwood, E. L. A procedure for removing the effect of response bias 
errors from waterfowl questionnaire responses. Biometrics, 
14(1): 132. March 1958. 
Hunters were asked to record on a calendar the number of hunting 
trips they made and the number of waterfowl they bagged in the different 
parts of the season. Data from the hunters who responded to this part 
of the questionnaire were used to estimate the proportional distribu- 
tions of the kill and of hunter participation during different parts of 
the duck season. As used in the tables, percentage of hunters partici- 
pating during any given period of the season is the percentage of 
reporting hunters who listed one or more trips during that period. The 
kill data apply to all waterfowl, not just ducks, but probably fairly 
well represent the duck kill alone, because in most areas ducks make up 
the preponderance of the kill. 
Results concerning seasonal distribution of the kill were on 
slightly different bases in 1959-60 and in 1960-61. In 1959-60, 
hunters were asked to list only the duck kill on the calendar. It was 
evident, however, that many of them were in fact recording all water- 
fowl, for the'totals on their calendars exceeded the total number of 
ducks they recorded in other parts of the questionnaire. In the dis- 
tributional tabulations, an adjustment was made to. eliminate the reports 
that showed the total kill of coots plus geese to be greater than the 
total kill of ducks. The change in wording in the questionnaire for 
the 1960-61 season was made to improve consistency of response. 
RESULTS 
Waterfowl Kill 
The total number of ducks retrieved in the Mississippi Flyway 
during the 1960-61 season was estimated at 2,977,411 (table 1). This 
total was 6.8 percent larger than the total for 1959-60. When reports 
of canvasbacks and redheads were excluded from the data, the total for 
1960-61 was 9 percent larger than for 1959-60. Some canvasbacks and 
redheads were reported in 1960-61 even though the season was closed for 
them. 
Increase in the numbers of puddler ducks was greater than the 
average. There were two exceptions: pintail numbers increased less 
