Pennsylvania is unique with its complex topography and geographic position. The ridges of Pennsylvania are oriented in such a way that when prevailing winds strike the slopes of the ridges during fall and spring, updrafts are produced which result in optimal soaring/gliding conditions along the ridges for migratory birds. Tens of thousands of raptors and songbirds cruise along the ridges and the Allegheny Front in their migratory movements along the Atlantic and Appalachian Flyways. Logically, many targeted wind development sites are lands located on these ridges along key raptor migration corridors. These ridges also currently comprise large intact forest blocks that support a diversity of breeding interior forest songbirds. Siting wind turbines on “brownfields” (post-industrial sites) rather than large, intact forest blocks would minimize such fragmentation and reduce impacts.
In addition to birds, several species of mammals, especially bats, and reptiles, particularly rattlesnakes, may be impacted by wind turbine farms. Bats are particularly vulnerable to atmospheric pressure changes near the turbines rotating blades. The Pennsylvania Game Commission has signed cooperative, voluntary agreements with companies developing wind energy in Pennsylvania to avoid, minimize and potentially mitigate any adverse impacts the development of wind energy may have on the state’s wildlife resources. Brokered with substantial input from wind energy industry representatives and assistance from the Pennsylvania Wind and Wildlife Collaborative (PWWC), the Game Commission’s “Wind Energy Voluntary Cooperation Agreement” provides guidance and consistency, in the absence of compulsory regulations for private lands, for development of wind turbines sites, which have become one of the state’s fastest-growing industries.
Pennsylvania Game Commission Minimization efforts from Wind Turbine Cooperators include the following:
1. Reduction of overall project size to minimize wildlife impacts.
2. Additional evaluation and/or elimination of project areas within ten miles of known hibernacula containing the federally protected Indiana bat.
3. Avoidance of existing forested landscape and use of disturbed lands to the maximum extent possible.
4. Placement of turbines on reclaimed strip mine lands to avoid land clearing.
5. Elimination of planned turbines on ridge tops near raptor flyways.
6. Turbines set back 50 – 400 m off escarpments to minimize potential raptor collisions.
7. Movement of turbines 30 – 100 feet away from potential woodrat habitat.
In addition, the PA Audubon Society suggests that lighting of turbines is to be avoided, so as to not attract nocturnal migrating bird flocks. Similarly, adjacent communication and meteorological towers should be lit using rapidly pulsing white strobes to avoid attracting nocturnal migrants into wind farms. Guy wires at turbines and adjacent towers increase mortality risk, and should be avoided. Similarly, power transmission lines should be run underground.
You’ll want to check out: Ridgetop Important Bird Areas, Raptors and Wind Turbines (Audubon) and the PA Game Commission’s Wind Position Papers.
Also helpful are the current wind power guidelines of the US Fish and Wildlife Service.