. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. Sandwich terns are distinguishable by their bicolored bills prefer sandy nesting habitats, the islands quickly become useless. Parnell says there could be problems in the future for the sandy nesters if too many diked, dredged islands became heavily vegetated or if the corps continues to deposit more and more of its dredge material on beachfront or mainland areas. A 1983 census of all nesting colonial water- birds in North Carolina, conducted by Parnell, showed a decline in the pop- ulations of least terns
. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. Sandwich terns are distinguishable by their bicolored bills prefer sandy nesting habitats, the islands quickly become useless. Parnell says there could be problems in the future for the sandy nesters if too many diked, dredged islands became heavily vegetated or if the corps continues to deposit more and more of its dredge material on beachfront or mainland areas. A 1983 census of all nesting colonial water- birds in North Carolina, conducted by Parnell, showed a decline in the pop- ulations of least terns, common terns, gull-billed terns and black skimmers— all bare-sand nesters. Parnell points out that new deposits of dredge material or other manage- ment tools such as tilling, applying plant retardants or burning could be used to keep vegetation at a minimum. Scientists are just beginning to study methods of altering or creating nesting habitats for colonial waterbirds. In the 1983 census, sponsored by UNC Sea Grant and Army Corps of Engineers, Parnell found that four percent of the colonial-waterbird nests occurred on barrier-island sites; 18 percent on natural estuarine islands; 27 percent on diked, dredge- material islands; and 51 percent on un- diked, dredge-material islands. He also learned that populations of brown pelicans, white ibises, laughing gulls and royal terns had increased since his 1977 census. After comparing the 1977 and 1983 censuses, Parnell found that the water- birds were nesting at fewer sites, but that the sites in use were supporting larger colonies. This trend has Parnell worried because dense aggregations of birds at relatively few breeding sites might mean a single catastrophic event, such as an epidemic, could spell disaster for a large percentage of birds. But it's not only habitat degrada- tion that has ornithologists wor- ried about the waterbirds' future. Sci- entists are also concerned about the encroachment of man. "There's a re
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Keywords: ., bookcentury1900, bookcollectionunclibra, booksubjectoceanography
