Sunning (behaviour)

[1][2] Swallows were observed to indulge in the activity for very short durations and this appeared to induce hyperthermia leading to them gaping to cool.

[3] A theory that birds obtained vitamin D by allowing precursors in the preen-gland secretions to be converted by ultraviolet radiation is considered to be unsupported.

[6] Another theory is that ectoparasites may be killed or forced to move away from inaccessible parts of the body to more accessible areas where they can be removed through preening.

Lizards, crocodiles, terrapins, and snakes routinely make use of the morning sun to raise their body temperature.

In the higher latitudes, many insects have black on their wings or body to enhance their heat acquisition.