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Title: Colonial nesting sea and wading bird use of estuarine islands in the Pacific Northwest
Authors: Peters, Carl F.
Richter, Klaus O.
Manuwal, David Allen
Herman, Steven G.
Keywords: Estuarine ecology--Northwest, Pacific
Birds--Habitat--Northwest, Pacific
Island ecology--Northwest, Pacific
Sea birds--Northwest, Pacific
Shore birds--Northwest, Pacific
Publisher: U.S. Army Engineer Waterways Experiment Station
Series/Report no.: Technical Report (Dredged Material Research Program (U.S.)) ; no. D-78-17
Abstract: Twenty-three natural and dredged material islands were examined in seven locations from Anacortes, Washington, to Coos Bay, Oregon, to establish the relationships between plant communities and use by colonial nesting waterbirds for both types of islands, as well as the actual bird use of dredged material islands in the Pacific Northwest. Nine islands were found to be used for nesting by one or a combination of glaucous-winged gulls, western-glaucous-winged (hybrid) gulls, ring-billed gulls, Caspian terns,, and common terns. Colonies of great blue herons were found on two islands 61 and 97 km from the mouth of the Columbia River. Habitat maps were prepared for each island studied and detailed floristic descriptions of each bird colony evaluated. Colony location, breeding phenology, and nesting success were analyzed with respect to existing flora, environmental stress, island physiography, and human disturbance. Results showed that although dredged material deposition influenced an island’s physical dimensions, topography, and substrate, plant communities were physiognomically similar to natural islands. Seabird colonization occurred irrespective of dredging history. Nesting populations appeared to be greater in areas of low human disturbance. Colonization and productivity were primarily related to protection from environmental stress. Indications were that gull and tern nesting on dredged material islands is minimal compared to seabird productivity on natural islands. Management of dredged material islands should not be directed toward increased gull and tern production, but existing colonies should be maintained and monitored. Common terns are a unique addition to Pacific Northwest avifauna and should be protected. Dredged material deposition could improve habitat on some islands by providing increased stability and protection from environmental stress.
Description: Technical Report
Gov't Doc #: Technical Report D-78-17
Rights: Approved for Public Release; Distribution is Unlimited
Appears in Collections:Technical Report

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