An important component of effective management of waterfowl and other migratory game birds is "mortality" which can be thought of as having two parts - natural and hunting mortality. While harvest surveys do not in themselves provide an estimate of the harvest rate (the proportion of the population harvested), they do provide an estimate of the number of waterfowl taken. Estimates of harvest rates are determined from banding data.
Unlike a number of other surveys conducted by waterfowl managers, harvest surveys require the cooperation of hunters to obtain the necessary information.
The first nationwide harvest survey - or Hunter Success Survey - occurred in the US in 1952 and produced estimates of harvest for each of the four flyways. Estimates for individual states were first made in 1960. Canada began its national survey in 1967. Since Canada requires a federal permit to hunt waterfowl, they have a database from which to ask hunters about their harvest. Prior to 1998, the only federal requirement to hunt waterfowl in the US was to buy a "Duck Stamp." So a sample of hunters were asked to participate in the survey when they bought their "Duck Stamp". (Please see the paragraph on HIP below.) At the end of the season, hunters were asked to report where they hunted, the number of days hunted and the number of ducks and geese taken. In the first years of the survey in the US, hunters were also asked to list their harvest of individual species of waterfowl. But since 1961 in the US and 1968 in Canada, the composition of the harvest - the percent of the harvest each species contributes - is determined by another survey called the Parts Collection Survey (PCS).
The genesis of the PCS was with Aelred D. Geis, who began the research in the late-1950's to determine if duck wings could be used to the determine if a bird was hatched in the year it was harvested or was an "adult". Samuel M. Carney began working on the project in 1958 and showed that "a trained observer (using a combination of feather shape, pattern, color and wear) could correctly identify ages and sexes" of ducks. Sam reported "I remember being so elated the day I knew the method would work that I wore a necktie!" (Flyways). He ultimately published Species, Age and Sex Identification of Ducks Using Wing Plumage in 1992.
A sample of hunters are asked to send one wing from each duck and the tail and primary wing feathers of each goose killed to a central point in each flyway in the US with a similar procedure being implemented in Canada. Hunters report the location and date of kill. Biologists then "read" the duck wings according to criteria described by Sam Carney to determine species, sex and age and the feathers of geese to determine species and age.
The information from the Hunter Success Survey (HSS) is combined with that from the PCS and band recoveries to provide a picture of the waterfowl harvest. In addition, these data can provide an index of what the composition (the age and sex ratios for each species) of the fall flight was, providing a check of the data collected during the breeding season.
Concerns about the efficiencies of the HSS in the US to provide a sound sampling frame of hunters and the identification of the need to estimate the harvest of all migratory game birds - doves to ducks and swans to snipe - brought about significant changes beginning in 1992. That was the first year of the Harvest Information Program (HIP) and three states participated in a pilot program. Under HIP, all migratory game bird hunters must register in the state where they intend to hunt. Hunters provide their name and address and an estimate of their harvest the previous year. This latter data allows the USFWS to "stratify" their sample, collecting the most information from hunters most likely to hunt a particular species.
The requirement to register under HIP was phased in across the country and hunters in all states (except Hawaii) fell under the rule in 1998. A sample of hunters are contacted directly by the USFWS after they register and are asked to keep track of their harvest and hunting activity. The cooperation of hunters remains a critical component of obtaining good harvest estimates. The old method of estimating harvest was conducted along with the new HIP driven methods until the 2002/2003 hunting season when only estimates from HIP will be available. Much more information about HIP is available in Harvest Information Program: Evaluation and Recommendations and from the USFWS web site.
A separate mail questionnaire is used to estimate sandhill crane harvest in the Central Flyway and more information is included in the Flyway specific section.