When John Salazar interrupts a phone interview with a reporter to hop off his tractor on his farm in the San Luis Valley to get an oil filter for his son who’s working on another tractor, it’s not performative. As Salazar, a self-described “old buzzard” who turns 73 in July, explains simply, “I’m working like a fool, but I love it.” There’s another animal, however, that leaps to mind when talking the economy and politics with Salazar, who’s the …