According to refuge manager reports in Aircraft Overflight Issues , military overflights can pose a direct threat to the establishing purposes of individual refuges. These purposes include providing habitat for endangered species and maintaining preserves and breeding grounds for migratory birds, waterfowl, and other species. In most cases, overflights disturb nesting or migrating raptors, waterfowl, and shorebird populations.
Overflights can also disturb mammals such as bighorn sheep, antelope, walrus, seals, and sea lions.
The Buenos Aires NWR in Arizona was specifically established under the Endangered Species Act to preserve a mesquite grassland for the reintroduction of the federally endangered masked bobwhite quail, while Nevada's Ash Meadows NWR provides critical habitat for 33 federal or state listed endangered, threatened, and candidate species. Migratory Birds and Waterfowl Threatened As the Aircraft Overflight Issues report points out, a number of affected refuges are critically important to migrating birds. New Jersey's Forsythe NWR, for example, provides wintering habitat for approximately 10 percent of the Atlantic flyway's black duck population and approximately 15 percent of the Atlantic brant population. Up to two million birds spend at least part of their winter at California's Sacramento NWR complex, including over half of the pintail ducks in North America. Sequoyah NWR in Oklahoma is the main Central Flyway wintering ground for mallard ducks, New Mexico's Bitter Lake NWR sees a large portion of the world's population of lesser sandhill cranes, and California's Farallon NWR is home to the largest continental seabird breeding colony south of Alaska.