ORNITHOLOGY 
PART I 
PHYSICAL FEATURES, IHIiABITATS, BIOGRAPHICAL 
NOTES AND REVIEW OF FAUNAL LISTS 
Chester county lies in the southeastern part of 
Pennsylvania, bordering the states of Delaware and 
Maryland from the Brandywine to the Octoraro, 
and extends northward to about 40° 15’ on the 
Schuylkill. With the exception of the extreme 
southeastern townships, its area of 780 square miles 
is a part of the Delaware river system. Chester val- 
ley cuts through the centre in a southwesterly direc- 
tion at a depth varying from 200 to 400 feet, and 
from 500 to 2,000 yards wide for practically the 
entire distance of 30 miles; dividing the county 
in not unequal parts. For almost two hundred years 
this valley has been almost entirely deforested and 
under cultivation; in consequence its wild animal 
life is less varied than that of the wooded hills on 
either side. It would appear, however, that the 
Killdeer, Red-headed Woodpecker and Grasshop- 
per Sparrow are more constant breeders here than 
elsewhere in the county, and the Mallard and Black- 
crowned Night Heron are peculiar to the broad and 
deep eastern part. 
The northern half of the county is a succession 
of hills and vales to the Welsh mountain (elevation 
728 feet above the sea at Waynesburg). [rom the 
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