Draft Baseline Report - Least Turn and Piping Plover Section

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Chicks fledge approximately 21 days after hatching, but they are not competent at fishing until after fall migration from the breeding grounds (Whitman 1988, Wilson 1991). Until then, the parent birds share feeding the young. The least tern is piscivorous and prey almost exclusively upon small schooling fish within the 1 to 3 -inch size range (Atwood and Kelly 1984, Wilson et al. 1993). Adult birds and chicks also consume terrestrial invertebrates (Wilson et al. 1993). Prey Species Sizes of forage fish brought back to nests in 1989 were primarily < 1.02 inches (2.6cm) in length (83 %), and in 1990, 88 % of fishes brought to nests were less than 1.52 inches (3.8cm) in length (Wilson et al. 1993). Lingle (1988) reported the diet of least terns to be comprised of 1 -2 inch fish. Wilson et al. (1993) listed prey fish brought to nests as red shiners (Notropis lutrensis), creek chubs (Semotilus atromaculatus), white suckers (Catostomus commersoni), Plains killifish (Fundulus zebrinus), gizzard shad (Dorosoma cepedianum), largemouth bass (Micropterus salmoides), and other species of cyprinids. Lingle (1988) collected specimens of fish lying in the sand within the least tern colony, which included sand shiner (Notropis stramineus), red shiner (Notropis lutrensis), and river carpsucker (Carpiodes carpio). In addition, terns were observed feeding on Plains killifish (Fundulus zebrinus) (Lingle 1988). Terrestrial invertebrates consumed were described as flying and crawling insects in close vicinity to the nest. An adult least tern was observed changing its flight direction momentarily to capture a dragonfly (Wilson et al. 1993). Foraging Movements Terns nesting at sandpits use the nesting sandpit, the adjoining river, as well as other sandpits for foraging and loafing. In both 1988 and 1989 least terns nesting adjacent to sand pits did not forage solely at the nearest available sand pit, but traveled to forage elsewhere (Wilson et al. 1993). In 1979, Faanes (1983) reported that most sandbar nesting least terns foraged in river channels within 100m of the nest sites. Lingle (1988) reports that least terns generally forage within one mile of their nest site. Once fledged the birds become mobile and utilize other locations for foraging and loafing, which may include other sandpits and the river. Following nesting, least terns congregate in areas, apparently to feed and prepare for migration (Lingle 1988). In Nebraska, fall migration usually takes place from mid- or late July to early September (NGPC 1997). The congregation sites are used up to 30 days, and are typically used by more adult birds than can be accounted for in the local colonies (FWS 1997). Piping Plover Foraging Ecology Draft Baseline Report, July 2002 4 -9