Warren County
Warren County lies in northwestern Pennsylvania within the Appalachian Plateau Province. Northern and western regions of the county are within the Glaciated Pittsburgh Plateau section; the remaining regions of the county are within the High Plateau section of the province. Topography ranges from gently dipping hills modified by glacial scour and till deposition in glaciated areas to relatively broad northeast-trending mountains that decrease in amplitude northward in the High Plateau section. Cool, mixed coniferous forests, deranged wandering streams, and marshes and bogs support plant and animal species characteristic of northern boreal forests.
Cool Finds
Toplovich's Bog, found in the glaciated northwestern part of the county, supports a unique plant community that includes slender cotton-grass (Eriophorum gracile), a Pennsylvania species of special concern; bog-rosemary (Andromeda polifolia); cranberry (Vaccinium sp.); pitcher plant (Sarracenia purpurea); and sundew (Drosera sp.).
Also found near the southern limit of its range in Warren County is creeping snowberry (Gaultheria hispidula), a member of the heath family (Ericaceae) that smells of wintergreen when crushed. This species gets its name from its trailing leafy stems and white fruit. A small population was found along Queens Creek within a hemlock palustrine forest.
The Swainson's Thrush, a Nearctic-Neotropical migrant bird that breeds as far north as Alaska and northern Canada and winters primarily in South America, breeds in Warren County. 
Considered to be Pennsylvania's rarest thrush, this state species of special concern is robin-size with an olive back, spotted breast, and buffy eye-ring. Chances are you will not detect this bird by sight, but by its distinct rising flutelike song. The Swainson's Thrush nests in the shrub layer of forests and is associated with conifers, especially hemlock and spruce in Pennsylvania. Several breeding pairs have made their home in Heart's Content National Scenic Area within the Hickory Creek Wilderness Area of the Allegheny National Forest in the southeastern part of the county.
Populations are declining for this thrush species, even in areas of the country where it is abundant (Mack 2000*). Possible factors for decline include loss of breeding or wintering habitat, forest fragmentation, and collisions with large towers and tall buildings during migration. The Swainson's Thrush also appears to be sensitive to human activity around nest sites throughout breeding season, especially during egg laying (Mack 2000*). Important habitat attributes on their breeding grounds are canopy closure, understory cover (for nests), tree density, and conifer component.
*Evans Mack, D., and W. Yong. 2000. Swainson's's Thrush (Catharus ustulatus). In The Birds of North America, No. 540 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Calendar
o The county signed an agreement with the Western Pennsylvania Conservancy to conduct a natural heritage inventory in September 2004.
o An advisory committee was organized and our first advisory committee meeting was held on May 3, 2005 in Warren.
o A slide presentation on the Warren County Natural Heritage Inventory was given to the Northern Allegheny Conservation Association on July 28, 2005.
o A second advisory committee meeting will be scheduled for sometime in early winter for review of the inventory results from the 2005 field season.
Contact
For questions relating to the Warren Co. Inventory, please contact:
Rita Hawrot
Ecologist
Western Pennsylvania Conservancy
209 Fourth Avenue
Pittsburgh, PA 15222
(412) 586-2319
rhawrot@paconserve.org