Due to the effectiveness of the government program to exterminate the wolf in the nineteen-teens and early 1920s, by 1925 wolves had ceased to present any significant problem to ranchers except for the occasional wolf that crossed into the U.S. from Mexico. In the mid-twenties, PARC (Predator and Rodent Control) agents developed the preventative strategy of patrolling the few remaining habitats in the U.S. and posting their most effective wolfers along the border; men such as W. C. Echols.
There were years when no wolves were killed in New Mexico except for those taken by Echols on the border, indicating both the success of the government’s campaign to eliminate the wolf and Echol’s skills as a wolf-hunter. He killed about four wolves a year until 1933, when the lessening of American livestock interests in Mexico and the country’s discontinuance of its wolf control efforts led to increases in its wolf population and consequently those that crossed into the United States. Between 1933 and 1943, Echols took between 6 and 9 wolves every year except one.