Birds feathers reflect UV light and it is this plumage reflection which plays a part in sexual selection. Breeding should be more successful with UV light present. UV light also plays a significant role in the selective intake of food. Ripe fruit and berries appear as a different colour to the bird. What a bird see affect its appetite.
Reds are redder and greens are greener.
A reluctant feeder needs UVA light to simulate its appetite. Vitamin D3 is required by birds for healthy bone development. Many species can synthesize D3 from sunlight through their skin. Specifically it is the UVB light within the spectrum that enables D3 synthesis. The Arcadia Fluorescent Lighting Controller Suitable for use with Arcadia and other fluorescent tubes.