You might find this article helpful. It explains F/S lighting in terms that us common people can understand! LOL
What is full spectrum light?
Full spectrum light is the name we give to the light produced by the sun after it passes through the earth's atmosphere. In the tropics (where most companion birds' ancestors originated) the sun's light reaches the earth in its most undiluted form. In captivity we use various fluorescent lights to try to reproduce sunlight as closely as possible. The parts of sunlight we are most interested in reproducing are in the ultraviolet spectrum - in particular UV A and UV B light.
It is a small segment of the UVB (sometimes referred to as "middle ultraviolet" light) that causes Vitamin D synthesis in the skin. Most people studying this agree that the UVB light needs to be somewhere between 290 and 310 nanometers in wavelength for this to occur and a Color Temperature of >5000 Kelvin. Less generally known are the benefits of another part of full spectrum lighting - those caused by UVA (also called "near ultraviolet") light. To my knowledge all of the commonly kept companion birds are diurnal (daylight dwelling). The cycle of light to dark in any given part of the planet is known as its circadian cycle (which roughly translates as "about a day"), and the sunrise to sunset segment is known as a photoperiod. Birds have many very complex responses to photoperiod in their behaviors and metabolism. Birds perceive this photoperiod in two ways:
1) The primary way they achieve this is through their eye. The retina of a bird's eye can perceive a great variety of information about the intensity, color make-up, and direction of light. The information is transmitted to two different areas - to the part of the brain responsible for vision and to the pituitary gland.
2) UVA is the specific type of light that the Harderian Gland senses. As mentioned earlier, this is one of the primary ways that the normal circadian clock cycle is adjusted and how triggers for reproductive and migratory behavior are provided. Any quality full spectrum bulbs with a CRI (Color Rendering Index) of 90 or higher contain enough UVA to achieve this.
The Color Rendering Index (CRI) is a scale developed to rate how closely an artificial light compares to natural sunlight at high noon. High noon sunlight is assigned a value of 100. No artificial light source attains a CRI of 100. The bulbs we use with our birds have a CRI index of 91 to 96.
NOTE: Sunlight that passes through the windows of your home has upwards of 90% of the beneficial UV spectrum filtered out by that glass - unless that glass was made pre-1939. Studies have shown that the aluminum screening used in many homes can filter out 30% or more UV light. High-grade acrylic (like that used in our acrylic cages) filters out 5% or less of the UV light).
What lights should I use for my birds?
Rather than making recommendations on what particular brands of lights to use I would instead suggest that the companion bird owner request that the light manufacturer send them specific data (including a spectral analysis) of their bulbs UVB output, its CRI rating and a comparison graph showing how long it holds its spectrum. Using the information above should help you determine whether or not the bulb is a good choice for your companion bird or not. Any company that will not produce this data and guarantee it should (in my opinion) be avoided. I would suggest using tube lighting (usually available in 2 and 4 foot lengths) first as they have the advantage of a larger interior surface area in which to place the phosphor coating which creates the specific spectrum of light thrown by the bulb - some even have special indentations (the Power Twist Bulbs by Duro Vita-Lite) to maximize this area. Compact fluorescent bulbs have a smaller area for the phosphors to adhere to but I have found several bulbs that have a high CRI index of 91 to 96 as well as a UVB output of between 290 and 310 nanometers wavelength. The only true benefit of the compact version of these bulbs is their ease of use as they can be used in most fixtures that will accept a standard light bulb socket - in comparison to mounting the fixtures needed to hold a tube light.
How we recommend using full spectrum lighting:
These lights should be placed so that the bulb is located within two feet of the bird. When the bird is beyond two feet distance from the light the effect of the bulb are greatly lessened. (NOTE: Be sure that the bulb and any electrical cords are always out of the reach of your bird!) These bulbs should only be used with a light timer. Having these lights go on or off at even slightly different times of the day could potentially cause abnormal reproductive behaviors in your bird. Some of these potential problems are: territorial aggression, compulsive egg laying and excessive release of sexual hormones and adrenaline which several avian veterinarians (including Dr. Jenkins) and myself have seen cause health problems for these birds due to toxicities caused by their over-release (see earlier description of the Hyderian Gland and the Circadian Clock). Both of these behaviors are best avoided with our companion birds. We wish to use this lighting for durations just long enough for the proper assimilation of nutrients, but not so long as to potentially cause problems. We suggest different amounts of time for these lights to be on based on the species of bird it is being used with. These recommended times have changed (lessened) since 1994 when we first began our observational study of full spectrum light usage with companion birds.
It is also very important to set your timer so that the light is on during the normally brightest time of day so as to not add to the total photoperiod your bird receives. (Example: If the light should be on 6 hours per day a good time period would be from 9AM to 3PM - thereby not lengthening the bird's photoperiod as would happen in parts of the country where the length of outdoor light period shortens dramatically during he winter months, like Minnesota where we live, if the light were to remain on after 5PM).
The following time lengths are current as of a conversation with Dr. Tammy Jenkins in September of 2003:
Most smaller birds (cockatiels, parakeets, lovebirds, canaries, finches, etc…): One to two hours per day maximum.
Most African Parrots (Greys, Poicephalus, and most likely, Vasa Parrots), Eclectus and Cockatoos: Four to Six Hours per day maximum.
All other birds (including all South American Parrots): Two to Four hours per day maximum.
