Analyzes data from the 1984 and 1986 Federal Waterfowl Hunter Questionnaire Survey (WHQS) to estimate the rate of retu rn of name and address contact cards, to evaluate the efficiency of the survey's stratification scheme, and to investigate p otential sources of bias due to nonresponse at the contact card and questionnaire stages of the survey. Methods; Survey eff iciency; Primary nonresponse; Secondary nonresponse; Results; Discussion.