Development of the largest natural gas fields in the continental United States is driving wildlife from traditional wintering grounds, conservationists say. Researchers from the Wildlife Conservation Society using GPS collars to track 125 female pronghorn in Wyoming\'s Jonah and PAPA gas fields found an 82 percent decline of habitat classified as \"highest quality,\" meaning highest probability of use for wintering animals, the society said in a release Wednesday. Natural gas development in these areas has led to a sharp increase in well pads, roads and other associated infrastructure, researchers said, which in turn is driving pronghorn to the periphery of areas historically classified as crucial winter ranges. \"In our study we have detected behavioral shifts for pronghorn in response to natural gas field development and infrastructure on federal BLM [Bureau of Land Management] lands,\" Jon Beckmann of the society\'s North America program said. \"Maintaining the integrity of crucial wintering areas is particularly important in harsh winters to avoid diminishing pronghorn numbers.\" Fifty percent of North America\'s pronghorn live in Wyoming, while numbers are declining in other parts of the United States, the society said, warning pronghorn can only lose so much winter range before they will begin to decline in population.