A wild horse band from the Calico Mountains, in June this year.
The Bureau of Land Management is seeking public input on its plan to muster 2476 to 2787 wild horses from what is known as the Calico Mountains Complex.
The current estimate of horses inhabiting the complex is 3095, based on modelling and an aerial count in September.
It proposes releasing up to 264 horses back into the wild, which would leave the region with about 572 horses, in line with what is considered an appropriate management level.
Most of the remaining horses will end up in holding facilities, already home to at least 32,000 mustangs pulled from the western rangelands.
The bureau, in its 43-page preliminary environmental assessment, said the appropriate management level for horses across the complex was 572 to 952 wild horses.
Winter time on the Black Rock Range.
The bureau said the potential gather area would extend beyond the herd management area boundaries as wild horses had moved outside the areas in search of food, water and space.
It proposes to begin the gather in about December. It is expected to take about three months due to potential winter weather delays and the logistics involved in moving traps and holding sites many times.
"Winter gathers in this area are preferred as foals are older and wild horses are down off of the highest elevations, reducing the travel distance to trap site locations.
It said the horses needed to be removed to achieve and maintain appropriate herd numbers and prevent further range deterioration resulting from overpopulation.
"Managing wild horse populations within this number is expected to assure a thriving natural ecological balance and multiple-use relationship within the Calico Mountains Complex.
"Results of drought conditions is evident throughout the Complex with low forage production in some areas and decreased water flows, although spotty June rains did help forage production and several dirt reservoirs caught some runoff."
A new Spring foal in the Calico Mountains, pictured in June.
"The gather would also benefit the health of wild horses remaining in the complex by reducing competition for forage and water."
It said the gather was needed to prevent deterioration of animal health and reduce impacts to rangeland and wildlife resources from overgrazing by wild horses.
The planned muster has gone out for public consultation in the same week the Equine Welfare Alliance called for a moratorium on the removal of wild horses.
It argued that authorities were running more gathers and in some cases had "zeroed out" some herd management areas. It said it feared for the ongoing genetic viability of some herds, given the limited numbers left in some areas.