Habitat Types. Nene are reported to utilize a variety of habitats from sea level to 8,000 feet above mean sea level including coastal dunes and non-native grasslands (such as golf courses, pastures and rural areas), sparsely vegetated low and high elevation lava flows, cinder deserts, native alpine grasslands and shrublands, open native and non-native alpine shrubland-woodland, as well as mid-elevation native and non-native shrublands and early successional cinderfall (USFWS 1999). However, their present distribution was highly influenced by the location of release sites for captive-bred nene and nesting generally occurs in areas associated with release sites (Xxxxx 1988, Xxxxx et al. 1999, USFWS 1999). It is unlikely that nene used native grasslands, grassy shrublands and dryland forest prehistorically (Xxxxx et al. 1999). Little is known about the vegetation structure, dynamics, and composition of Hawaiian habitats, especially in the lowlands, prior to human contact. However, more recent archaeological work is improving our understanding of the environmental history of Hawaii, including species composition and this is likely to aid in habitat restoration efforts for all native species, including nene (Xxxxx et al. 1999, Xxxxxx et al. 2001, Xxxxxxx and Xxxxx 1990). Nene have shown flexibility in the utilization of alien plants and readily forage on introduced grasses and other plant species, however, low productivity is believed a problem in nene populations due to insufficient protein intake in their diet and there are also concerns about whether adequate nutrition is available for goslings (Xxxxx and Xxxxx 1995, Xxxxx et al 1999, Black et al 1994). Recent studies of habitat use and on the nutritional value of various food items eaten by nene, including native and non-native plants, will aid in determining methods for converting predominantly non-native plant communities into habitats dominated by native plants that are capable of sustaining nene populations in appropriate areas agreed on by nene managers and stakeholders (Xxxxx et al. 1999, Black et al 1994, Hu 2000, USFWS 1999, Woog 2000).
Habitat Types. Stilts use a variety of aquatic habitats but are limited by water depth and vegetation cover. Stilts require early successional marshlands with water depth less than 24 cm (9 in); perennial vegetation that is limited and low growing such as nonnative pickleweed, California grass, and seashore paspalum or knot grass (Paspalum spp.); or exposed tidal flats. Native low-growing wetland plants associated with stilt nesting areas include water hyssop (Bacopa monnieri), sea purslane (Sesuvium portulacastrum), and the sedges makaloa (Cyperus laevigatus) and Kaluha (Bolboschoenus maritimus) (Xxxxxxxx et al. 1999). They may also use taro (Araceae) ponds where the full grown vegetation forms a protective canopy. Stilts are rarely found in wetlands above 200 meters (m) (660 feet (ft)) elevation. Ephemeral lakes on Molokai, Maui, and Niihau are important for stilts. Management techniques that mimic seasonal inundation and evaporation of freshwater mudflats would be beneficial to nesting silts and provide invertebrate forage for their young. Insular mudflats are isolated from terrestrial predators, but are still susceptible to avian predation. On the island of Hawaii, anchialine ponds provide important foraging habitat for the Hawaiian stilt. Prawn farms, which have numerous ponds in perpetual drawdown and flood-up, provide excellent foraging habitat for adult birds. Stilts generally forage and nest in different wetland sites, moving between areas daily. Adults with three day old chicks have been observed to move 0.5 kilometers (0.3 miles) from the nest site (Xxxx and Oring 1993). Nesting sites are adjacent to or on low-relief islands within bodies of fresh, brackish, or salt water. These bodies of water include irrigation reservoirs and settling basins, natural or man- made ponds, marshes, and taro patches. Breeding Habitat Stilts prefer to nest on freshly exposed mudflats, interspersed with low growing vegetatio n. The nest itself is a simple scrape on the ground. They have also been observed using grass stems and rocks for nesting material (Xxxxxxx 1981; X. Xxxxx, pers. comm. 1994). Nesting also occurs on low relief islands (natural and man-made) in fresh or brackish ponds (Xxxxxxxxxxxxx 1977). Higher nesting densities are found on large mudflat expanses interspersed with vegetation (U.S. Fish and Wildlife Service 1983). Stilts have also been observed successfully using man- made floating nest structures on Kauai (X. Xxxxxx, pers. comm. 1988) and floating wooden plat...
Habitat Types. Xxxxx are usually found on the coastal plain of islands where wetland habitats are more common and they are generally found below 400 meters (m) (1,320 feet (ft)) (USFWS 1999). They prefer habitat with a suitable mix of open water and emergent plant growth and are usually found in fresh or brackish water. Xxxxx have been observed in upland plunge pools above 1,500 m (4,922 ft) elevation on Kauai (USFWS 1999). Breeding Habitat The optimum nesting habitat is in wetlands with a 50:50 to 75:25 mix of dense emergent vegetation and open water (USFWS 1999). Xxxxx nest on open water and in small openings in xxxxx vegetation (Xxxxxxxxxxxxx 1977, Udvardy 1960). Taro ponds provide some of the best habitat because of shallowness, presence of vegetation, and constant water levels. They usually construct floating nests of aquatic vegetation or semi- floating nests anchored to emergent vegetation (Xxxx et al. 1985). Nesting occurs primarily between March and September although nests have been documented from all months (Xxxxxxxxxxxxx 1977). Diet Xxxxx usually forage in water that is less than 30 centimeters (cm) (11.8 inches (in)) deep although they can dive up to 120 cm (47.2 in) deep (USFWS 1999). Xxxxx prefer more open habitat than the Hawaiian subspecies of the common moorhen (Gallinula chloropus sandvicensis). Xxxxx are generalists and utilize food sources on the water surface, by diving, by foraging in mud or sand, and also by feeding in upland grassy areas near wetlands, including golf courses (USFWS 1999). Diet items include seeds and leaves of aquatic plants, invertebrates including snails, insects, and crustaceans, tadpoles, and small fish (Xxxxxxxx and Xxxxxxxx 1949). References American Ornithologists’ Union (AOU). 1993. Thirty- ninth supplement of the American Ornithologists’ Union Checklist of North American Birds. Auk 110: 675-682. Xxxx, X.X., X.X. Xxxxxxx, X.X. Xxxxxxxxxxxxx, and X.X. Xxxxx. 1985. Notes on the breeding biology of the Hawaiian race of the American coot. 'Elepaio 45: 57-63. Engilis, A., Xx. xxx Xxxxx, X.X. 0000. Status and population trends of Hawaii’s native waterbirds, 1977-1987. Xxxxxx Bulletin 105(1):142-158. Marshall, A.P. and X.X. Xxxxxxxxxxx 0000. Mariana Common Moorhen research and wetland conservation. Pp. 46-51 in CNMI Division of Fish and Wildlife, Wildlife Research Program, annual report FY 1995. 106 pp. Xxxxx, X.X. 1978. Do mainland xxxxx occur in Hawaii? 'Elepaio 38: 73.
Habitat Types. As is typical of island waterfowl, koloa exploit a wide range of geographically distinct habitat patches such as coastal marshes, lowland agricultural fields, stream plunge pools, ephemerally flooded pasture, stock ponds, and montane bogs ranging from sea level to 9,900 feet elevation. Agricultural wetlands supplement natural habitats and provide important foraging, mating, and xxxxx-xxxxxxx xxxxx (XXXXX 0000x). Little is known about the habitat requirements required to meet annual life cycle needs (such as pair bonding, nesting, brood rearing, molting), or other environmental factors limiting recovery. On the Big Island, the highest number of koloa is found in the mid- to upper-elevation stock ponds and streams of the Xxxxxx-Xxxxx Xxx Xxxxxx (Xxxxxx 0000). An estimated 200 koloa are distributed from sea level to 6,400 feet elevation from Hawi to Puu ‘O‘o in the north windward areas (Xxxxxx 1983, Engilis and Xxxxx 1993). The captive bred koloa dispersed up to 25 miles from release sites and were observed in seeps, stock watering ponds, small reservoirs, ditches, and streams of the Kohala-Mauna Kea Region. The pen-reared birds were found to be surviving and reproducing in the Kohala ponds at rates higher than other sites (Kosaka 1973). (Appendix A, Figure 1. Koloa Historical and Current Distribution) Big Island mountain streams favorable to koloa are characterized as 500-4000 feet in elevation, approximately 23 feet wide, banks 2-75 feet high and heavily vegetated, water clear, shallow and swift flowing, rocky bed with many potholes, and minimal disturbance (Xxxxx 1981, Xxxxxx 1983). In the stock ponds, Xxxxxx (1983) found koloa activity to be highest in complexes of small, clustered ponds located near a perennial stream. Today the Kohala-Mauna Kea ponds continue to provide important habitat, especially those isolated from human activity, with open water and exposed mudflats (X. Xxxxxx, Hawai‘i DOFAW, pers. comm. 1999). Xxxxxx (1983) recommended the modification and construction of reservoirs and stock ponds for the benefit of waterfowl.
Habitat Types. Nēnē inhabit a variety of habitats from sea level to 8,000 feet. Habitat types occupied by nēnē include alpine scrublands, lava flows, cinder deserts, mid-elevation native and non-native shrub lands, grassy coastal dunes, golf courses, and grazed pastures (USFWS 1999b). The current distribution has been highly influenced by the location of release sites for captive-bred nēnē. Nēnē usually inhabit areas with less than 90 inches of annual rainfall (USFWS 1999b). The presence of open or flowing water is not necessary for successful breeding, but recent observations of the nēnē in lowland coastal areas indicate that open water, when available, will be readily utilized (USFWS 1999b). These open water areas in wetlands can provide protection from terrestrial predators such as rats and mongooses.
Habitat Types. Nene utilize a variety of habitats from sea level to 8,000 feet including coastal dunes, non-native grasslands (such as golf courses, pastures and rural areas), sparsely vegetated low and high elevation lava flows, cinder deserts, alpine grasslands and shrublands, open native and non-native alpine shrubland-woodland community interfaces, and mid-elevation native and non-native shrublands (USFWS 1999). The current distribution of nene has been highly influenced by the locations of release sites for captive-bred nene (Xxxxx 1988, Xxxxx et al. 1999).
Habitat Types. 7.30 The characteristics of each of the habitat types within the Study Area are presented under the following sub-headings. Habitat characterization is based upon the typical vegetation communities present and the degree of habitat stratification.
