The Avian Sun™ 5.0 UVB Compact Fluorescent provides birds with safe  levels of beneficial UVB and UVA for physical and psychological health.  UVB enables birds to synthesize vitamin D3 for proper calcium metabolism  which is necessary for normal growth, maintenance of strong bones, and  egg production. UVA is visible to birds, enabling them to recognize  mates, locate food, and identify different species. Without UVA, birds  are essentially colorblind!