The toco toucan (Ramphastos toco), the largest member of the toucan family, possesses the largest beak relative to body size of all birds. This exaggerated feature has received various interpretations, from serving as a sexual ornament to a refined adaptation for feeding. However, it also represents a significant surface area for heat exchange. We have demonstrated the remarkable capacity of the toco toucan to regulate heat distribution by modifying blood flow, using the bill as a transient thermal radiator.  Our results indicate that the toucan's bill is, relative to size, one of the largest thermal windows in the animal kingdom, rivalling elephant's ears in its potency to radiate body heat.