Arizona Congressman Raúl M. Grijalva criticized a Bureau of Land Management (BLM) decision to create nonreproducing herds in two Wyoming Herd Management Areas (HMAs) as detrimental to wild mustangs and burros, and claimed that the agency’s herd census methods are flawed.

In a July 5 letter to Secretary of the Interior Ken Salazar and BLM Director Bob Abbey, Grijalva, a member of the House Committee on Natural Resources, asked the BLM not to geld stallions or spay mares to achieve nonreproducing herds on grounds that the castration and spay procedures endangered animals’ lives and that under the Wild Free-Roaming Horse and Burro Act of 1971, sterilization should not be used to create nonreproducing herds.

"Although sterilization is mentioned in the Wild Free-Roaming Horse and Burro Act, it is intended to reference population control, and not the creation of completely nonreproducing herds, which would result in the extinction of wild horses in their legal herd areas," Grijalva wrote in the letter.

Grijalva suggested the agency use natural controls including predator management to control herd growth: "Predator management through mountain lions has been enormously successful in stabilizing the population of the Montgomery Pass herd on the California-Nevada border. Due to predation of foals by mountain lions, that herd has not had a roundup in almost 30 years