Denver 1936

Black text on a white background with a black and white illustration in the center of a burro loaded with supplies

The phrase "Rocky Mountain Canary" came about as a reference to the loud brays made by burros—also known as donkeys—that were used by early prospectors in the American West to transport supplies and equipment. As the mining industry changed and declined over the course of the early twentieth century, burros began to be used in the timber industry. In addition, the sport of burro racing was developed in the 1930s as a way to help find a use for the over-populated animal. Burro races continue to be held: as of 2023, the Western Pack Burro Association holds races in five Colorado towns with mining histories during the summer season.