6 

 river valleys, while such distinctly Alleghanian forms as 

 the Chestnut-sided Warbler, Purple Pinch, Savanna Sparrow, 

 and Black-capped Chickadee occur. 



The Alleghanian and Pocono Mountains - On the 

 main ridge of the Alleghanies from the northern counties 

 south to Somerset, on the Pocono Mountain plateau and on the 

 plateau region of north-central Pennsylvania, there once 

 existed, and still apparently exists, a bird fauna decidedly 

 Canadian in its affinities. Now, however, the destruction 

 of the coniferous forest which formerly covered these mount- 

 ains has in most places driven away the most typical north- 

 ern birds which bred in the damp dark woods. Dr. Dwight, in 

 an interesting article in the Auk (1892, pp 129), writes as 

 follows concerning the region about North Mountain, Sullivan 

 County, as it existed at that time:- 



"The forest is truly primeval; the hemlock, the 

 yellow birch, and the maple are the characteristic trees 

 and attain great size. The hemlocks are scattered in con- 

 siderable numbers thru the forest and tower above it, their 

 huge trunks often four or five feet in diameter, marking 

 them out giants among their lesser brethern. The underbrush 

 4s often dense, and everywhere great logs, covered with moss, 

 lie mouldering. Here and there you hear clear cold brooks 

 that seem to imitate the song of the Winter Wren that is 

 almost constantly heard among them. The drawling song of 

 of the Black-throated Blue Warbler and the sprightly one of 



