HUMAN IMPACTS ON WATERBIRDS 



Since the late 1800s many human activities have had both positive and negative 

 effects on waterbird populations. Disturbance during the breeding season, 

 loss of valuable feeding and nesting habitat, and environmental contamination 

 by oil, heavy metals, and organochlorine compounds are currently the major 

 threat to waterbirds in Maine. Some of the positive effects of people in 

 coastal Maine include the protection of waterbirds by law, the preservation of 

 certain key waterbird colonies, and the inadvertent creation of upland feeding 

 areas for shorebirds partial to cleared land. 



This section will discuss how habitat loss, environmental contamination, and 

 disturbances by people affect waterbirds. 



Habitat Loss 



Excessive loss of important breeding, feeding, and nesting habitat is 

 detrimental to most waterbirds. Losses include the complete elimination of a 

 specific habitat such as the filling of a wetland or construction on most 

 small islands. Sheep grazing or timber harvesting on bird islands may 

 seriously reduce nesting cover. Terns, laughing gulls, and Leach's storm 

 petrels have been affected the most by these activities (Drury 1973) . 



Tidal Power 



Tidal power, which is yet to be developed in Maine, is given special 

 consideration here because the feasibility of developing several large scale 

 tidal power projects has been under investigation (Cobscook Bay in region 6 

 and Taunton Bay in region 5). 



Impoundments created by tidal barrages are likely to adversely affect birds 

 that feed on intertidal mudflats and in the vicinity of deepwater tidal rips. 

 The degree to which an estuary or the adjacent marine deepwater ecosystems 

 will be affected depends on characteristics of the estuary and the type of 

 generation facility used (e.g., turbine type, one or two pool impoundments, 

 and position of the sluice). Several generalizations based on existing and 

 planned tidal obstructions may be made. 



The area of intertidal mudflats that is presently exposed is likely to be 

 reduced because tidal amplitude is reduced (especially along the lower tide 

 range), water is temporarily impounded and will cover mudflats (feeding areas 

 will be available for shorter periods of time) , and water may be inadvertently 

 obstructed by the barrage (i.e., the area below lower turbine level) or 

 deliberately retained for peak power generation beyond the normal period of 

 low tide. 



Increased sedimentation behind the impoundment may alter the species 

 composition and abundance of mudflat invertebrates (Yeo 1978; Risk et al. 

 1977). Such changes occurred in a barrage-like impoundment in the northern 

 Bay of Fundy (Yeo 1978). Lower densities and biomass of important shorebird 

 foods, such as the small amphipod Corophium volutator , were found in the 

 substrates behind the obstruction. Lower shorebird numbers also have been 

 reported in that area (personal communicatione from S. Boates , Acadia 

 University, Wolfville, Nova Scotia, Canada; June, 1979). Species most likely 



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