On a January morning in the foothills of the Andes, Gonzalo Cardona Molina gave his daughter a goodbye hug, jumped on his 2015 Yamaha motorcycle and set off for the habitat of the elusive yellow-eared parrot. Cardona had spent two decades nurturing the rare bird, a species once thought extinct. Now, they numbered in the thousands, and he was their protector — the overseer of the wild preserve in this South American nation where they thrived anew. A preserve that happens to abut one of Colombia’s most notorious drug routes. “God willing, I will be coming back to you soon,” the 55-year-old told his daughter. Three days later, a search party found his body in a shallow grave with two bullets in his chest. His slaying was the latest in a deadly wave of killings of environmentalists in Colombia, a nation where they are fast becoming almost as endangered as the species they strive to protect.