The report is something of a shock, because this epic annual event by some very large and numerous animals apparently has been taking place undetected for generations.
But it's a game-changer because we now know that mule deer, instead of being homebodies who spend their lives in a limited habitat, are migrators that - like ducks and geese - need a variety of habitats over a larger landscape.
Just as we have long known waterfowl need uplands and seasonal wetlands as well as those larger permanent wetlands, we now know muleys not only need habitat protected from development in the desert and mountains, they also need safe and nourishing habitat along the entire migration corridor.
And that corridor currently finds them crossing three highways and more than 100 fences, as well as many reservoirs and rivers.
The study (and video) will be solid ammunition for conservationists battling what has often been a blind rush to develop of oil and gas in the same areas with little consideration to the impact on wildlife - and the substantial sport-hunting economy they support.
Just as removing wetlands in Missouri could impact ducks moving from nesting areas in the Dakotas to wintering grounds in Louisiana, chopping up migration corridors could have a profound effect on these animals.
Ed Arnett, head of its Center for Responsible Energy Development, said the report reinforces many of its main points.
"If we do not safeguard all the pieces of that puzzle, including important habitats associated with migration, big-game populations likely will decline and impact both our outdoor traditions and our hunting-based Western economy," he said.