Relation of Summer Birds to Western Adirondack Forest 407 



raspberry and other fruit-hearing shrubs of the region. Here the 

 dearth of tall trees has restricted the number of species of birds, 

 the absence of the Robin and some other familiar species being 

 especially noticeable. The following species were found nesting 

 here : Olive-backed Thrush, House Wren, Catbird, Redstart, Yel- 

 low-throat, Chestnut-sided and Nashville Warblers, Red-eyed Vireo, 

 Cedar Waxwing, Rose-breasted Grosbeak, Song and White-throated 

 Sparrows, Goldfinch, Least Flycatcher and Flicker. This clearing 

 was freely visited by most of the birds of the neighborhood at vari- 

 ous times in the season, for in midsummer it abounds with wild 

 fruits ; and it is likely that it was the most popular bird resort of all. 



The general influence of clearings in a forested region on the local 

 summer birds is well worth inquiry, as it produces a new order of 

 ecological conditions. " By the ecological distribution of birds," 

 says Dr. Charles C. Adams ('08, pp. no, 122) "is meant that cor- 

 relation between environmental conditions and the occurrence and 

 association of certain species of birds. . . . Every field naturalist 

 has observed the general correlation of certain birds with certain 

 kinds of vegetation." He defines (I.e., p. 128) bird succession as "a 

 change from the dominance of certain species or associations to that 

 of others." Cary ('n, p. 34) shows that deforestation in high moun- 

 tains in Colorado results in warmer local conditions, and conse- 

 quently in an upward extension of the plant growth from below. 

 Sunlight overspreads the ground, and the open spaces begin to pre- 

 sent new forms of vegetation serviceable as cover and forage for 

 insectivorous and fruit-eating birds. The occurrence of a greater 

 variety of bird life in a clearing than in virgin forest is wholly in 

 accordance with a fundamental law of ecological succession as given 

 by Adams ('08, p. 125) : "Where dominance obtains, avian variety 

 is limited so that the greatest diversity occurs where local influences 

 prevail, and at the margins of the formation." A clearing projects 

 into the area of dominance a " margin," or a progressive series 

 of " margins," productive of greater diversity than could be the case 

 while the original forest held sway over the area. By this same law 

 we account for the great variety of bird life in the Barber Point 

 neighborhood, since it presents many local features of open campus, 

 partial clearing, habitation clearing, burned tract, lumbered clearing, 

 bog forest, meadow and dense forest, besides secondary factors of 

 lakeshore and brookside. Each minor habitat or secondary factor 

 creates a " margin " in the original forest, inducing the fullest 

 diversity of species. 



In the western Adirondack region, the clearings, where the soil 

 is unaffected by fire, become quickly covered with berry-producing 

 shrubs, including elderberry, blackberry, raspberry, blueberry and 

 others, and the birds are more and more attracted td clearings as 

 these fruits spread. Among the newcomers are Warblers, Sparrows 

 and others that require a bushy covert. Furthermore, the shrubbery 

 is prolific in insect food, and hence an additional influence is exerted 

 upon the insectivorous birds to attract and hold them as tenants of 

 the clearing. 



