FAUNAL POSITION. 



139 



istic C'anadian birds undoubtedly never occur. But these are non- 

 migratory species, and it becomes plain, with this fact in view, that 

 the limited extent and isolation of the Catskill region renders their 

 absence in the face of favorable conditions easily explicable. The 

 higher mountain b\auna of the Catskills may therefore be regarded 

 as purely Canadian in character. 



Between those altitudes where these simplified faunal conditions 

 prevail and the lower valleys, we may trace the two approximating 

 Faun:e in every degree of union. The result is that we find species 

 of totally different distributional relationship occup\ing the same 

 ground. This is easil\- illustrated : While such species as the Win- 

 ter Wren, Black-throated Blue, Black-and- Yellow, Mourning, and 

 Canadian Fly-catching Warblers, Blue-headed X'ireo, and Slate-col- 

 ored Snowbird, occur certainly as low down as i,5oo -1,600 feet, 

 species of much more southern distribution, as the Chewink, Field 

 Sparrow, House Wren, Wood Thrush, Indigo Bird. Large billed 

 Water Thrush, and Bluebird (named approximately in the order of 

 their altitudinal limitation from below upward) extend 10 an altitude 

 of from 2,000 to perhaps 2,5oo feet. 



Further details regarding the local distribution of species appears 

 in the following review of the birds, in which, with respect to a very 

 limited portion (already defined, page 117) of the great Appalachian 

 Mountain s^■stem, the facts reofardinof the summer Avi fauna will, so 

 far as brief but continuous and careful observation could discover 

 them, be presented. 



As has already been said, the geographical scope of the present 

 paper is restricted to the southern Catskills. But as this section of 

 the region can claini the highest of the mountains, it seems probable 

 that few it any birds of the Canadian F"auna are regular summer 

 residents in the northern Catskills which do not also occur in the 

 southern. 



Unless otherwise stated, all references to the region are to the Big 

 Indian Valley and the adjoining mountain slopes in Ulster County, 

 the whole section being included in the township of Shandaken. 



