1908 (Brewster 1924), and in Casco Bay (region 1) between 1880 and 1900 

 (Kendall 1902). Norton reported that wading birds showed a marked increase 

 for three decades after protection, which was followed by another decline for 

 which he gave no explanation (Palmer 1949). During this period the only 

 colonially nesting species were the great blue heron and black-crowned night 

 heron. 



Wading birds in general are probably more abundant in Maine today than in any 

 previous period. Evidence for this is indirect, however, as no systematic 

 inventories were conducted until the mid-1970s. Currently, all species of 

 wading birds, except the black-crowned night heron, are increasing in Maine. 

 The number of species breeding along coastal Maine is also increasing. The 

 snowy egret first nested in Maine in the early 1960s. The glossy ibis, little 

 blue heron, and Louisiana heron now breed in Maine south of region 1, and 

 nonbreeding individuals of these species have been observed in all six regions 

 of the characterization area. 



Present Status of Wading Birds 



Breeding birds . Of the six species of wading birds breeding in the 



characterization area, the great blue heron, black-crowned night heron, and 



snowy egret nest in single or mixed-species colonies, and the green heron and 

 least and American bitterns nest solitarily. 



There are 22 nesting colonies of wading birds in the characterization area, 

 most of which (90%) are on islands. The location of each colony is plotted on 

 atlas map 4. The great blue heron is the most abundant colonial nesting 

 wading bird (table 14-15). Over 900 pairs nested in 19 different colonies 

 during 1977 (Korschgen 1979; and Tyler 1977), which constituted the largest 

 breeding population of any state north of New Jersey (Osborn and Custer 1978) . 

 Seventy-nine pairs of black-crowned night herons nested in four colonies along 

 coastal Maine in 1977, and seven pairs of snowy egrets nested in two colonies. 

 The snowy egret is at the northern limit of its breeding range in Maine. 

 However, it is extending northward and can be expected to nest in other 

 locations in the characterization area in the future. Three other species of 

 colonial nesting wading birds, the little blue heron, Louisiana heron, and 

 glossy ibis, are also extending their breeding ranges northward. These 

 species currently nest along the Maine coast south of the characterization 

 area . 



Breeding populations of green herons, and least and American bitterns are more 

 difficult to determine than those of colonial nesters and are currently 

 unknown. The green heron is common around estuarine intertidal emergent 

 wetlands, where it nests in trees. It also may be found in palustrine 

 wetlands. The least and American bitterns nest on the ground in emergent 

 vegetation such as cattails, bulrushes, and sedges. The American bittern is 

 fairly common in palustrine habitats and, to a lesser extent, in estuarine 

 intertidal emergent wetlands. The least bittern is known to nest at only two 

 locations in Maine; a brackish marsh in Newcastle (region 2) and Bear Brook 

 Pond in Acadia National Park (region 5). 



Wading birds arrive on their nesting grounds in early to mid-April. Eggs are 

 laid in late April and early May and hatch between late May and June. Young 

 fledge from mid-July through early August. Most herons leave Maine in October 



14-37 



10-80 



