Birds of Allegany Park 241 



certain birds, I have grouped the species in the main text, in 

 ecological associations, rather than in taxonomical order. Because 

 bird life is directly or indirectly dependent upon other forms of 

 wild life, and primarily upon the vegetation, I have described at 

 some length these associations and the principal kinds of plants 

 found in each. It is of course true that no two species of birds 

 live under exactly the same ecological conditions. Some species 

 grouped in one association occur also in others, not all individuals 

 of the species living under the same conditions. Within the same 

 association, different species live differently, dependent in a dif- 

 ferent way upon it. Some species depend upon conditions in one 

 association for a nesting site, but obtain their food chiefly within 

 another, the individual living in two or more associations. For these 

 reasons it is often difficult to determine in which association to 

 place a given species, and the grouping is therefore somewhat 

 artificial. 



A complete ecological study means a study of each species and 

 its interrelations with various plants, insects, mammals, other birds, 

 and all forms of wild life which constitute its associates and 

 enemies. It also includes food, nesting sites or nesting materials 

 and the complete physical habitat. Such an extensive study is 

 beyond the scope of this work, but the outlining of general bird 

 ecology of the region will serve as a foundation for detailed studies 

 in the future. It is obvious that the abundance of a species in a 

 given region is determined not merely by geographical range but 

 also by the conditions within the association in which it must live, 

 and by the relative abundance of other forms of life in that asso- 

 ciation which affect it. This makes the study of the ecology of 

 birds of primary importance in working plans for the conservation 

 of bird life. 



Within each association I have listed the species in the approxi- 

 mate order of their abundance. This order was determined partly 

 by general observation, and partly by making counts of singing 

 birds along the roads, or at points in the forest. I made allowances 

 for the fact that some species had slackened or ceased singing be- 

 fore my arrival in the region, and that in the case of certain species 

 some individuals cease to sing for long periods, so that all indi- 

 vidual males are never completely in song together through the 

 nesting season. 



This list is based upon a study of the birds of the region occupy- 

 ing a period from July 3 to August 13, 192 1. During this time 

 an effort was made to cover as much of the Park area as possible, 

 and particularly to include areas widely varying in character. 



For those who are beginning a study of birds, or who know 

 only a small number of the commonest species, a mere local list is 

 not of great value. For this reason I have included the section on 

 the identification of birds in the field, and the field key. I have 

 not tried to give full and complete descriptions of birds such as 

 might be made from a study of skins or mounted specimens, but 

 have emphasized mainly the field characters of each species. De- 

 tailed descriptions are not of great use to the outdoor student as 



