Why is it necessary to protect a bird from direct sunlight during summer?

It is essential to protect a bird from direct sunlight during the summer primarily because they can overheat. Birds have a relatively high body temperature and can be at risk of heat stress or heatstroke if exposed to extreme temperatures and direct sunlight for prolonged periods. Overheating can lead to serious health issues and even be life-threatening.

In addition to overheating, humidity plays a significant role in a bird's ability to regulate their body temperature. In hot weather, birds may struggle to cool down effectively, making shade and a cool environment critical for their wellbeing.

While it might be true that some birds are adapted to arid conditions, they still require protection from the direct, intense rays of the sun. Moreover, while vitamin D is important for birds, they can receive it through safe exposure to sunlight without necessarily being in direct sunlight at extreme heat levels, thereby negating the idea that maximizing sun exposure alone is beneficial without considering their comfort and health.