Piping plover and least tern populations and habitat in western Iowa : final report, 1989.

(1989) Piping plover and least tern populations and habitat in western Iowa : final report, 1989. Iowa State University

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Abstract

During the 1900s, humans have converted much of the middle Missouri River from a slow-moving, meandering river into a narrow, fast-moving stream. These changes have been dramatically documented in Iowa. From 1890 to 1976, the river length adjacent to Iowa decreased by 32.2 miles (-15S). The sandbar area on the Iowa side of the river declined even more dramatically, going from 17,559 acres in 1890 to only 43 in 1976 (-99.85). Just since 1947, the sandbar area has declined from 7,991 to 43 acres (-99,5~)(Hallberg et al. 1979). This change has meant that sandbars and their associated open, early seral-stage habitats rarely form on the river. The Piping Plover (Charadrius melodus) and Least Tern (Sterna antillarum), two species that typically nest on these sandbars, are especially affected by these habitat changes. In 1986, the u.s. Fish and Wildlife Service classified the Northern Great Plains population of the Piping Plover as a Threatened species, indicating their concern for its continued survival. In 1986-87, its population numbered an estimated 1,376-1,444 pairs nesting in six states and four Canadian provinces (U. s. Fish and Wildlife Service 1988). Historically, a few Piping Plovers have nested on sandbars along the Missouri River in western Iowa. The inland population of the Least Tern is classified as an Endangered species. In 1987, its population was estimated at 4,515 adults (Sidle et al. 1988), In recent years, both species have nested on fly ash deposited by power plants near the river. Two colonies are located in Iowa: one near Council Bluffs (plovers and terns) and another near Sioux City (plovers, also terns in 1986)(see Tables 1 and 2). These sites have been surveyed periodically in recent years to determine the number of birds using them and their breeding success (e.g., Wilson et al. 1983, Wilson 1984, Williams 1985). The goal of this project was to continue this monitoring in 1988,