The Rocky Mountain Arsenal is not your typical National Wildlife Refuge. Seventy years ago, the United States Army used the land to produce mustard gas, incendiary weaponry, and dump chemical materials. Later, Shell Chemical Company started producing harmful insecticides and herbicides. And in 1987, it was declared as one of Earth's most polluted pieces of land! However, today it is home to bison, prairie dogs, and 330 other thriving wildlife species. The Rocky Mountain Arsenal, located ten minutes outside of downtown Denver, Colorado, offers one of the most unique urban wildlife refuges in the country.
Last week, on December 8, 2015, the Rocky Mountain Arsenal rounded up the bison herd to gather animals that had been selected for donation to the Crane Trust--a bison conservation organization--and for disease monitoring. For the US Fish and Wildlife Service and the staff who helped at the roundup, it was an exciting day filled with rambunctious calves, picture snapping, and sample taking. But for the bison, their experience was quite different.
Starting a week prior to the roundup, Rocky Mountain Arsenal managers slowly started to remove the bison's more distant water sources as a way to influence their movement towards alternative water sources in the grazing areas closer to the corral. This year, over half the herd moved on their own to a final area referred to as the "triangle."
On December 8th, once the equipment setup was complete and staff members attended the safety meeting, the roundup began right after sun up. Staff used pickup trucks to help encourage the bison's movement from the triangle to the "spin pen" and put them in groups of ten. While the spin pen may seem like the name of an amusement park ride, it is actually the first corral where the bison come to be moved by a skidsteer (a small, engine powered machine often used for construction) into the "circular maze" of the corral. The circular design allows the animals to move freely while reducing the chance of injury. The bison are then individually moved through the alley with holding stations, each with metal gates and doors. Staff members were reminded of the wildness of these animals as the banging and grunting of frustrated and nervous bison were heard throughout the day at the Arsenal.