Sunshine is necessary for budgie health. Its important that light is not shining from the sun through a window and directly onto the cage. Sunlight needs to be filtered, or broken in some way. I take my birds outside to get fresh air and light, but keep them in a shaded position, where they get bright indirect light. If I do put them in the sun, its in the morning, and they have a towel/cloth over part of the cage to keep it shaded at all times.