The decision resulted from a legal challenge mounted by the Colorado Wild Horses and Burros Coalition, the American Mustang and Burro Association, the Cloud Foundation and Front Range Equine Rescue over a BLM plan to remove all wild horses from what is known as the West Douglas Herd Area.
Federal District Court Judge Rosemary Collyer, sitting in District of Columbia federal court, accepted the argument of the groups that the BLM's plan violates the Wild Free-Roaming Horses and Burros Act.
She rejected the BLM's argument that its decision to remove the West Douglas Herd was a reasonable exercise of its discretion.
"The court finds that BLM's decision to remove the West Douglas Herd exceeds the scope of authority that Congress delegated to it in the Wild Horse Act," the judge said.
The West Douglas Herd Area encompasses 123,387 acres of federal land managed by BLM and 4754 acres of private land in Northwestern Colorado, southwest of the town of Rangely and about 50 miles north of Grand Junction.
The BLM counted 45 wild horses in the Douglas Creek herd unit but 36 were located east of the highway on land that is currently in the Piceance-East Douglas Herd Management Area.
The judge outlined the BLM's intentions to remove horses from the area, which dated back to 1980.
On July 14, 2008, the latest BLM edict requiring their removal was issued, with the use of helicopter drive trapping, helicopter-assisted roping, water trapping, or bait trapping.
The gather never occurred due to a lack of funding.
The BLM told the court that the problem in maintaining wild horses in the West Douglas Herd Area is a major shift in wild horse grazing-use patterns that has occurred since the early 1980s.
It is probable that intense energy exploration and development occurring in the northern part of the herd area has concentrated the horses in the south, resulting in overgrazing of the Texas Creek drainage, and horse use of Missouri and Evacuation Creeks that are not a part of the 1971 herd area.
"Against this backdrop, the defendants take the extreme position that it is within BLM's discretion to remove the entire West Douglas Herd, a herd comprised of wild free-roaming horses."
The specific issue here, said the judge, is not whether BLM may remove an entire herd of wild free-roaming horses and burros, as the BLM asserts, the issue is whether BLM may remove an entire herd of wild free-roaming horses and burros that the department concedes has not determined to be "excess animals" within the meaning of the Wild Horse Act.
"The court finds that Congress clearly intended to protect non-excess wild free-roaming horses and burros from removal, and that BLM's removal authority is limited to those wild free-roaming horses and burros that it determines to be 'excess animals' within the meaning of the Wild Horse Act.
"Congress did not authorise BLM to 'manage' the wild horses by corralling them for private maintenance or long-term care as non-wild free-roaming animals off of the public lands.
"Upon removal for private adoption and/or long-term care, the West Douglas Herd would forever cease to be 'wild free-roaming' horses 'as components of the public lands', contrary to Congress's intent to protect the horses from capture.
"Moreover, the statute expressly provides that BLM's 'management activities shall be at the minimal feasible level ... It is difficult to think of a 'management activity' that is farther from a 'minimal feasible level' than removal."
The judge said there was no procedure in the statute for removing non-excess animals.
"While it is true, as defendants argue, that nothing in the statute expressly precludes BLM from removing non-excess animals, it would make no sense for Congress to provide detailed procedures for removing excess animals but no procedure at all for removing non-excess animals.
"In light of the statute's purpose to protect wild free-roaming horses and burros, the court finds that the only plausible inference to be drawn from the omission of any procedure for removing non-excess animals is that Congress did not intend for BLM's management authority to be so broad."
Summarising, the the judge said a prerequisite to removal under the Wild Horse Act is that the BLM first determine that an overpopulation exists and that the wild free-roaming horses and burros slated for removal are "excess animals".
"BLM concededly has not made such a determination with respect to the horses in the West Douglas Herd Area."
The judge ruled, therefore, that the gather plan should be set aside.