The Necessity of Full-Spectrum Lighting
by Terry Beaudoin
For upwards of 30 years aviculturists, breeders, and avian veterinarians have recognized the benefits of using specialized lighting over birds that are native to areas of the world that receive huge amounts of the most undiluted sunlight to reach the earth.
Because of the benefits I have seen in my own birds (breeding pairs years ago, as well as my companion birds) and in hundreds of our customer's birds with the use of full spectrum light I feel that an article explaining it's usage based on those long term observations is overdue.
I would also like to thank Dr. Tammy Jenkins of St. Francis Animal and Bird Hospital for her contributions and willingness in offering her observations and insight into the physiological effects of lighting on companion birds.
How does full spectrum light effect companion birds?
Breeder aviaries, exotic bird collections and poultry production farms were some of the original places that full spectrum lighting was used and observed to demonstrate a definite positive effect. There were noticeable increases in the amount of offspring produced and in the survival rate of those offspring and their parents in facilities that switched to full spectrum lighting from the incandescent or standard fluorescent lights they had been using.
Exotic animal veterinarians would see birds and reptiles that exhibited signs of calcium deficiency even though their diet seemed to contain sufficient sources of calcium. One of the most obvious signs of this deficiency was observed in x-rays taken of these animals showing micro fractures in their bones as well as other signs of Hypocalcemia. Symptoms of Hypocalcemia are seizures, heart disorders, elevated blood cholesterol, soft-shelled eggs, bone disorders, nervousness, and tetany. Tetany is a condition where severe irregular muscle contractions and muscular pain occurs, due to the abnormal metabolism of calcium.
Years ago, when veterinarians first began noting the signs of Hypocalcemia in companion birds (primarily African Greys) many thought the problem was caused only by poor diet and lack of D3. The perceived remedy to the situation was to recommend a diet higher in calcium or calcium supplements as well as to give artificial (by injection or orally) a D3 supplement. Unfortunately, in many cases these doctors then saw eventual signs of Hypercalcemia in these same birds. Hypercalcemia, an abnormally large amount of calcium in the blood is caused by a high intake of calcium and vitamin D and may result in excessive calcification of the bones and some tissues, such as the kidneys or heart. D3 is a hormone necessary in animals (and humans) in order for the digestive tract to be able to extract calcium from their diet. Without sufficient amounts of D3 even large amounts of calcium supplementation will not benefit these animals. On the other hand if there are excessive amounts of D3 in the diet too much calcium can be taken in, causing the before mentioned Hypercalcemia. The correct level of D3 can be very difficult to artificially regulate. One of the greatest benefits of full spectrum lighting is the natural synthesis of Vitamin D precursors (calciferol and cholecalciferol) allowing the animal to naturally regulate calcium uptake.
Another important benefit of the usage of full spectrum lighting is the effect it has on the glandular system of the animal. The Thyroid and Pineal glands as well as the Hypothalamus control many of the most important functions in a birds system. The Thyroid Gland (Dr. Jenkins referred to it as the 'Master Gland') controls how and when the other glands function - for it to function properly it needs to be stimulated by normal photo periods of full spectrum light. The Hypothalamus is involved in proper feather development in birds. If there are problems with the Hypothalamus (Hypothyroidism) poor feather condition as well as skin (epithelial tissue) disorders usually occur. The Pineal Gland controls the cyclical processes in birds, such as molting and the reproductive cycle. The Pineal Gland is kept 'on track' by the animal being exposed to proper amounts of full spectrum light. To be specific: there is a special tissue that surrounds parts of the avian eye socket called the Harderian Gland. It is capable of sensing the duration of light which the bird experiences (the photo period). This information travels onwards to the pineal gland. The pineal and pituitary glands regulate much of the endocrine system and processes in birds. This is how the normal circadian clock (sometimes referred to as the "internal clock") cycle is "set". It also provides the triggers for reproduction and migratory behavior.
Most animals as well as humans have three-color vision (called trichromatic), while our companion birds have four-color vision (called tetrachromatic). In birds the lower wavelength ultraviolet (UVA) adds another visual perspective to the standard red, blue and green of our trichromatic vision. In areas lacking adequate UVA lighting the effect on birds is probably similar to a person who is colorblind.
Correct spectrum and photoperiod of light are also critical factors in normal preening behavior as well as the skin and feather health of birds. If a bird's system is not stimulated through adequate environmental lighting to maintain proper endocrine function, it may become lethargic and not continue normal preening behaviors. Normal preening removes debris and dander, which may build up on the shafts and barbules of the feathers. Regular preening creates supple feathers free of dirt, dust, chemicals and allergens that can accumulate on our companion birds just by living in our confined, well sealed homes.
- Incandescent lighting marketed as full spectrum can produce the same beneficial lighting as that produced by specially designed fluorescent bulbs. This is untrue: Incandescent lights provide a general lighting solution for work areas and living spaces. They are not full spectrum, and can never be engineered to be so, regardless of any manufacturers claim to the contrary. An easy way to determine this is to ask the incandescent bulb manufacturer to send you a guaranteed (preferably produced by a non-company affiliated testing facility) spectral analysis of their bulbs light output. So far, (in the few cases where the companies have been willing to send me information) I have not seen any incandescent bulb where the spectral analysis is remotely close to that of sunlight or the best of the full spectrum fluorescent bulbs.
- The flickering produced by fluorescent light bulbs is detrimental to our bird's health. This is a half-truth at best. Many veterinarians and bird owners have recently been worried about the possibility of flicker (pulsation) produced by fluorescent lighting. Older or cheap fluorescent fixtures have a flicker rate of about 60 cycles per second. Unless the fixture is malfunctioning or very old, we cannot perceive this flickering or pulsation. Our companion bird's eye and brain can perceive this flicker rate of 60 cycles per second produced by these older or malfunctioning fixtures or ballasts. Please remember that it is the fixture or ballast and not the fluorescent light which can cause this flickering.
The scare tactic used in bringing this matter to the attention of the bird keeping public is that birds are being "kept under a disco strobe light". The main problem here is that a number of avian veterinarians and parrot lecturers have become swept up in this concept, causing undue concern about potential and imaginary dangers. This is in complete disregard for scientifically established evidence which dispels any doubt that conventional full spectrum solutions are safe and beneficial to the physical, psychological, and endocrine health of birds. Some have even advocated switching to incandescent lighting which is improperly marketed as full spectrum.
The best way to avoid the possibility of any concerns about flicker is to use a modern fixture which contains an electronic ballast. Unlike magnetic ballasts, which are most commonly found in low cost and older fixtures, the electronic ballast converts the line voltage frequency to a much higher rate, generally 20,000-60,000 cycles per second as opposed to the line frequency of 60 cycles per second that older fixtures with magnetic ballasts can produce. Better quality ballasts operate above 42,000 cycles per second and avoid any possibility of discernable flicker that could be perceived by our companion birds.
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.
***In birds exhibiting excessive egg laying or other reproductive related problems we temporarily discontinue the light. (Consult your avian veterinarian for specific recommendations specific to your bird's situation).***
Because natural sunlight is the best source of full spectrum light we also recommend taking your bird outside as much as possible. Please feel free to consult us, your avian veterinarian or a trusted avian specialist for recommendations about the safest way to do this.
Editors Note: This article originally appeared in an edition of the Parrot Island Newsletter from 1996. It contains several revisions and has been updated in 2001 and again September 2003. It is based on the observations of several avian veterinarians as well as hundreds of companion bird owners who have been willing to document and then relate to us their observations about the perceived affect of lighting on their companion birds. Our thanks to all who have and still do contribute to our better understanding of the care of these wonderful animals.
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