The toucan uses its huge bill for thermoregulation

The video above is brief and silent; it depicts infrared thermal data of a toucan going to sleep (and tucking its bill under its wing). The toucan lowers its body temperature during sleep. To to so it shifts blood flow from its core to the uninsulated bill, where the heat then radiates out into the environment.

The process is discussed in more detail (and the video is narrated) at the BBC:

The birds' bills have a network of blood vessels that can increase or restrict the flow of blood.

Dr Tattersall said: "By altering blood flow to the bill's surface, toucans can conserve body heat when it is cold or cope with heat stress by increasing blood flow...

Other animals also use parts of their bodies to regulate temperature, for example, elephants and rabbits radiate heat from their ears to cool down.

But the sheer size of the toucan's bill means that relatively, it has one of the largest "thermal windows" in the animal kingdom.