Wood duck populations are currently considered to be increasing or remaining stable throughout much of their range. From 1959 to 1986, wood duck populations seemed to grow in the Atlantic and Mississippi flyways and elsewhere. Dr. Frank C. Bellrose, considered the world’s authority on wood duck ecology and management, estimated that from 1959 to 1986 populations grew by 9 to 16 percent per year in the Mississippi Flyway and from 7 to 9 percent in the Atlantic Flyway. Respectively, approximately 1.07 million and 1.65 million pairs of breeding wood ducks were estimated in the Atlantic and Mississippi flyways during the 1980s. Band recovery data from the mid-1980s to 1999 indicate that wood duck populations may have increased in the Mississippi Flyway in recent years. However, much of this growth may have been in peripheral areas recently exploited by breeding wood ducks. Estimated numbers of breeding wood ducks in the Pacific (60,000) and Central flyways (76,000) are much less, but populations appear to be increasing there, primarily because of nest box programs.
Several factors may have contributed to the overall population growth of wood ducks during the past few decades. Although drainage and clearing of bottomland hardwood forests continued, there was an increase in abundance and size of trees suitable for nesting by wood ducks, and a great increase in the numbers of beaver ponds and farm ponds. The wood duck’s favorite habitats are bottomland hardwood forest and other densely vegetated areas, but the bird has also exploited habitats of “secondary quality.” For example, wood ducks expanded their range into some habitats lacking ample bottomland hardwood forest, such as the northern parts of the Great Lakes states, areas of the Great Plains, and higher elevations of the Appalachian Mountains. Habitats such as sluggish prairie streams, marshes, and other locales that provide aquatic insects and some cavity trees or nest boxes can be beneficial to wood ducks. Because of severe population declines once incurred by wood ducks, it simply has taken time for the bird to reoccupy some habitats where it was formerly abundant, and to expand gradually into secondary habitats.
Despite existing techniques used to monitor wood duck populations, it remains difficult to know with a degree of precision how many wood ducks exist. The wood duck has a highly fragmented, forested breeding habitat across eastern North America. Also, wood ducks are extremely philopatric, meaning they tend to return to the same breeding location each year. Thus, these factors contribute to the difficulty of monitoring some subpopulations of wood ducks.
In 1997, the Wood Duck Population Monitoring Initiative was conceived. The objective of the initiative was to develop methods to 1) identify and estimate the size of subpopulations of wood ducks, 2) measure productivity of the birds, and 3) improve banding programs for wood ducks. Identification of subpopulations of wood ducks in North America is important so that region-specific management plans can be developed. One goal of the initiative is for biologists in eastern North America to leg-band more than 10,000 wood ducks annually, to derive meaningful survival estimates of the species. The objective of this goal for the eastern two flyways is apparently currently being satisfied. However, significant expansion of banding efforts would have to occur to provide reliable estimates for subpopulations of wood ducks within all of the flyways. Other techniques, such as monitoring of nest boxes and expansion of BBS routes, may be too logistically and financially prohibitive, at least at this time. Thus, there is current discussion over how wood duck population monitoring efforts will be enhanced in the future.
Wood ducks comprise approximately 10 percent or more of the annual duck harvest in the United States. Wood ducks were second, only to mallards, in total harvest in the Atlantic and Mississippi flyways in 25 of the past 30 years. From approximately 1959 to the late 1980s, total wood duck harvest increased in the United States, and was believed to be indicative of a general population increase. Approximately 560,000 and nearly 260,000 wood ducks were harvested in the Mississippi and Atlantic flyways, respectively, during that time; as few as 32,000 were harvested in the Pacific Flyway. In the 2000-2001 hunting season, between 1 and 1.3 million wood ducks were harvested in the United States. Thus, wood ducks continue to be especially popular among waterfowl hunters.
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