Why do birds sunbathe?
Bird sunning behavior can be captivating to watch, but why exactly do birds sun themselves?
Bird sunning is the act of spreading out in full sunshine to expose plumage and skin to direct sunlight. Different individuals and species will sunbathe in slightly different and specific ways. They are usually seen standing with the back to the sun whilst fluffing feathers on head and back to expose skin. Birds are also commonly stretching, spreading or drooping wings and tail whilst sunning. Sometimes they are also seen to raise wings to expose their underparts or flanks. Because the point of sunning is to capture the most sunlight, birds will frequently sun in open and unobstructed areas.
One has to differentiate this kind of behaviour from situations, where birds are trying to cool down by presenting themselves in a similar looking posture. The obvious difference will however be, that in this case these birds will seek the shade, and will not stay in the open sunlight, if they have got the choice.
So what are the reasons for sunbathing? In cold weather or early in the day, birds might sun themselves for warmth by taking advantage of solar radiation. This allows them to maintain their body temperature without expending as much energy from food.
Sunning does also help birds to convert compounds in their preening oil, which are secreted from a gland at the base of the tail, into vitamin D, which is essential for their health and wellbeing.
The most important reason for sunning, however, is to maintain feather health. Sunning will dislodge feather parasites because the rising body temperature and excess heat will encourage insects to move to other places in a bird’s plumage, where they can be reached and removed whilst preening.
Sunning does also help feathers to dry more quickly, so birds can fly easier, without being weighed down by excess water.
Last but not least, it is also likely that some birds sun themselves for pure enjoyment and relaxation.