Patrick R. Thrush © 1999
In many self improvement and recovery programs, there exists a group of people who are referred to as “Step Nazi’s”. Irrespective of the situation, they always believe that the answer to the problem is to be found in a simple program statement, and the absolute adherence to the principle that it embodies. One is never to question or analyze the merits of the statement, simply follow what is said, as it is given. Without lending any question to the matter, the avicultural community has fallen prey to “Step Nazi’s” in the form of lighting manufacturers and reptile keepers.
What is being referred to here is how lighting has been researched, developed, and applied to the specialty pet market. Much of what is given as ‘fact’ is actually marketing theorization and application of the needs of one species to another, dissimilar species. In examining this issue, we will look at three prominent myths which affect the buying and practice habits of the avicultural community.
MYTH # 1 - Birds require ultraviolet light for balanced health.
This half-truth sets the stage for all remaining misconceptions about ultraviolet light. It has long been understood that sunlight remedies many health conditions in humans, including rickets and seasonal depression disorder. Nutritional concerns revolve around the need for Vitamin D. It is here that perhaps the most confusion occurs. In general however, the popular consideration is that UV is required to maintain health.
In birds and many other mammals and reptiles, light travels through two completely different pathways to the brain. Certain kinds of lighting data, including quality, composition, and direction are sent from the retina to the pituitary gland. A very specialized tissue surrounding the eye, the Harderian gland, transmits information about light duration to the pineal gland. Combining the two pathways together, regulation is given to much of the organism’s endocrine and metabolic regulation.
Information transmitted through these links do not contain information from the ultraviolet. What does travel to the visual centers of the avian brain are images that are created by ultraviolet light. Birds have a tetrachromatic vision, meaning that low wavelength ultraviolet (UVA) is part of their visual spectrum. From this part of light, birds gauge the direction of light (polarization), and see plumage variations in other members of its species that humans cannot see.
The truth to the myth is that only low wavelength UVA affects vision and behavior in birds. It lends an adjusted perspective to the world of the bird, but all fluorescent and incandescent light sources produce at least some UVA as an artifact of their operation.
MYTH # 2 - Birds need ultraviolet to have adequate Vitamin D.
Skin is the largest organ of the human body. Its purposes are many, but unique among them is its ability to take sunlight and manufacture pre-vitamin D. Humans are not unique among members of the animal kingdom for possessing this ability. The most noted group for their survival need to do so are the reptiles. It is understood that without adequate levels of Vitamin D, species will suffer a variety of calcium deficient maladies. But is it necessary to be exposed to ultraviolet to maintain adequate D levels?
The answer to this is no. Consider humans and fur bearing mammals. Man now spends the majority of his time inside of buildings of one sort or another. He is shielded there, and in the vehicles he travels in by glass, which filters out the ultraviolet wavelengths. Yet rickets, a disease caused by Vitamin D deficiency is relatively unknown in advanced cultures. The reason for this is diet. Vitamin D is found as a supplement in milk and many other foods, is present in eggs, fish liver oils, and in tablet or capsule form.
Fur bearing mammals have only minute area’s which can absorb sunlight. Birds with their covering of feathers are not much different. In animals, much of the requirement for D is met through plant materials. Plants produce a version of Vitamin D, calciferol. This calciferol is then converted by much the same biological means as cholecalciferol, and used by the organism. In captive animals, calciferol and cholecalciferol are added as supplement to manufactured diets. D2, native calciferol is found in green plants and vegetables. In native environments, most of the Vitamin D intake of birds is through diet.
MYTH # 3 - Lights must have ultraviolet to be Full Spectrum.
In the 1960's, Dr. John Ott discovered that sources of light lacking in the upper and lower ranges of the spectrum could induce nervousness, fatigue, headache, disruption of sleep patterns, etc. By adding long wave ultraviolet to the lamp output of fluorescent devices, these conditions could be remedied. This gave birth to the first set of “full spectrum” lamps.
Since this time, major advances have been made in the technology of fluorescent light manufacture. Many companies now produce devices which provide a more natural light. They all use the same principle that Ott discovered, that light must be balanced into the blue and violet/UV end of the spectrum. But what most people do not realize is that in adjusting the visible portion of light upward, UVA (or near ultraviolet) becomes part and parcel of the lamp’s output. In today’s technology, even lamps which could not remotely be qualified as high color rendering, full spectrum devices put out quantities of UVA.
Reptile keepers have long needed a source of UVB to keep their animals healthy. It is a small segment of the UVB (middle ultraviolet) segment that causes Vitamin D synthesis in the skin. Reptiles must have these wavelengths, or suffer from Vitamin D deficiency. Recognizing that a real market exists for specialty devices, many manufacturers began production of “Full Spectrum” devices which contain quantities of UVB along with UVA and balanced visible light. Special use, special prices for production. The reality of this situation is that any fluorescent with a high CRI ( >90 ) contains balanced visual colors and quantities of UVA, which to your bird comprises the “full spectrum” of their visual range.
Taken together, we see that the “step Nazi” doctrine of full spectrum holds little credence for the practicing aviculturists. Proper diet and nutrition are the primary sources of Vitamin D for captive birds. Health is contingent upon balanced sources of both visual (to humans) and UVA energies. These energies are available in all high CRI lamps. UVB is not a necessary (although it can be helpful) component of Full Spectrum lighting. As such, use of forms of lighting which are high CRI general usage meet the requirement of light for birds. Combined with proper diet and environment, the myths can be laid aside, and high quality, reasonably priced lighting provided.
Cost translations of this are easy to see. Reptile keepers change their devices out every few months to a year due to the loss of the UVB component. But many of these devices still are more than adequate sources of quality general light. This is especially true for birds, where a UVB producing device such as Vita-Lite or Ott has a usable life of several years. This can result in sizable savings which can be applied to other aspects of your bird’s life!
Copyright 1999 by Patrick Thrush