EXECUTIVE SUMMARY 



The Maine coast provides an abundance and diversity of nesting habitats 

 for many kinds of birds. The objectives of this 2-year study (1976-1977) 

 were: to locate all nesting colonies of seabirds and wading birds in Maine, 

 north of Cape Elizabeth; to estimate the number of breeding pairs of each 

 species; to determine the breeding chronology of each species; and to identify 

 species population trends since 1900. A similar study was conducted in 1976 

 and 1977 for the region bounded by Cape Elizabeth, Maine and the southern 

 boundary of Virginia (Erwin 1979). Data for all of Maine have been incorpora- 

 ted into this report for the benefit of the Maine user-group. Population data 

 from the 1977 inventory are presented as baseline data. 



Surveys were flown each spring in fixed-wing aircraft to locate colonies 

 and to estimate populations of those species that are highly visible. Later 

 each colony site was visited by boat to determine species composition and to 

 estimate populations more accurately. Total nest counts, counts of breeding 

 adults, partial nest counts, and estimates of adults were felt to be the most 

 reliable inventory methods, in that order. A total of 353 colony sites was 

 found with an estimated population of 100,813 breeding pairs. Nineteen species 

 of sea and wading birds frequently nested at sites containing several species. 

 As many as nine species sometimes nested at such a site. The most abundant 

 nesting species on the coast was the herring gull, followed in order of abun- 

 dance by common eider. Leach's storm-petrel, double-crested cormorant, great 

 black-backed gull, 4 species of terns, 3 species of alcids, and 3 species of 

 herons. More than 220 colonies of herring and great black-backed gulls and 

 common eiders were located on the study area. Species with estimated total 

 populations of less than 150 pairs nested in only a few scattered colonies 

 along the Maine coast. Population estimates for all colonies of each species 

 are listed. Nearly 75 percent of the birds nested at sites that were pri- 

 vately owned. Diagrams depict the generalized nesting chronology for each 

 species. 



From historical data and the 1977 survey, population trends for some 

 species since about 1900 were identified. There were increases in abundances 

 for the double-crested cormorant, common eider, great black-backed gull, her- 

 ring gull, common puffin, and black guillemot. Decreases were noted for the 

 common and Arctic terns. Recent additions to the Maine coast nesting water- 

 bird list are the snowy egret, glossy ibis, and Louisiana heron. 



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