THE IMPORTANCE OF LIGHT

Light may be the cure for what’s ailing your bird. SUNLIGHT POWERS ALL LIFE ON earth, either directly or indirectly. Plants obviously must have sunlight or full-spectrum artificial light to manufacture their food by photosynthesis. Plants, in turn, pass on their energy to the animals that consume them. Light is also essential for the survival of most animal species. Animals that have evolved in total darkness (cave dwellers or deep-sea life. for example) do not require light, but nocturnal animals require low-level light.

For diurnal species (species that are active during the day), light is important for many reasons. Obviously, it is required for vision, and most birds have highly developed sight. For many species of animals, full-spectrum light is required for the conversion of cholesterol to vitamin D. Light and its changing cycles -- photoperiodicity is used by animals to synchronize their biological clocks. Full-spectrum light may be needed for the maintenance of health in ways still unknown, add, finally, light is important for the psychological well being of animals.

Avian species, including nocturnal birds, are highly dependent upon sight for survival. The avian eye displays the basic pattern of a vertebrate's eyes, but it incorporates many adaptations that have improved visual abilities. The avian eve is considered to be the finest ocular organ in the animal kingdom. The extremely large eye leaves little room in the head for anything else. For example. an ostrich eye is 2 inches in diameter, an owl eye is one-third the entire head weight, and the buzzard eye has four times the visual acuity (sharpness) of a human eye.

Photoperiodicity has long been studied in birds as a means of inducing reproduction. Day length is detected by the pineal gland. The adrenal gland is located in the brain between the cerebella hemispheres and the cerebellum. It has numerous functions, one of which is photoreceptor and regulator of circadian rhythms. Some photoreceptors are located deep within the brain and are not dependent upon the eyes for photoreception. The hormones of the pineal gland (melatonin primarily) affect sleep, behavior and brain electrical activity. There is also evidence that melatonin influences reproductive hormonal cycles by affecting the pituitary gland. This has been very important in inducing poultry to lay eggs and to maximize egg production.

Obviously, light cycling is most important in birds from northern or temperate climates where changes in the light cycle are the greatest. We often assume that birds living on the equator are not affected by day length, however, the slightly elliptical shape of the earth results in about a 20-minute change in light cycles that can affect reproductive cycles of equatorial birds.

Numerous breeders of exotic birds have used changing the day length in an attempt to manipulate breeding. however, few controlled studies have been conducted to assess its effects. Work at the department of avian sciences at the University of California at Davis and elsewhere demonstrated that long day lengths stimulate reproductive activity in cockatiels and blossom-headed parakeets. In general. birds must be exposed to short day lengths (10 hours of light, 14 hours of dark). before they can respond to long day lengths. The length of the photoperiod that may be stimulatory can only be determined experimentally for each species, but it may range from 13 to 17 hours. Ideally, it would increase gradually. Many birds will become unresponsive to this stimulus after prolonged! light stimulation. Work at UC Davis showed that cockatiels became resistant after two clutches. For pet birds, the sometimes prolonged or erratic photoperiods that they are exposed to in the home may affect them behaviorally. A bird exhibiting signs of sexual over stimulation or frustration (such as plucking) may respond to a shortened day length.

The effects of light on health may also be important in pet birds. Wild birds utilize sunlight for production of vitamin D3. Birds that are kept indoors and on a poor diet can develop a vitamin D deficiency. All seed diets are usually deficient in vitamin D and calcium. Vitamin D deficiency in growing birds results in rickets and bone fractures. A deficiency in adult birds can result in poor utilization of calcium and osteomalacia (loss of calcium from the bones), or hypocalcemia (low blood calcium). Birds that get no natural light should be supplemented with vitamin D3. The UV portion of sunlight that is necessary for vitamin D production will not pass through glass.

Vitamin D can be toxic, so be careful not to over supplement. Birds housed outdoors do not need supplemental vitamin D. Special Effects Light affects the health and well being of people and animals in numerous ways. Dr. John Ott did some of the pioneering studies in the 1960s and 1970s. He conducted numerous studies on the effects of light on plants and animals. He utilized time-lapse photography to demonstrate plant growth and the effects of limiting the photo spectrum. Working with fluorescent lights, such as cool white, daylight white. and warm white bulbs that were limited in spectrum, some plants would not flower properly. By using light filters to further limit the light spectrum he could produce signs suggestive of viral disease in plants. He conducted similar studies in mice and found that deprivation of part of the light spectrum could produce loss of fur, skin disease, curling and loss of the tail, and inflammation of the heart muscle (myocarditis). It also affected the behavior of the mice, making some aggressive and agitated. In studies of children in school where curtains were closed and limited spectrum fluorescent lights were used, children were hyperactive and inattentive. This behavior was corrected when the lights were changed and the curtains were opened. He also equated malillumination with malnutrition.

A recent Wall Street Journal report showed how light is being used to enhance human well being. Prior to the invention of the electric light in 1879, buildings were designed with an emphasis on placement of windows to enhance natural lighting. As architects relied more on electric lighting, natural lighting of buildings was reduced. The need for energy efficiency has again affected how we design our indoor spaces for light. Recently, European countries have begun to require that a percentage of a building's light come from outdoors -- 37 percent in the Netherlands, for example.

According to a report by the Rocky Mountain Institute in Snowmass, Colorado, increasing daylight results in fewer days lost to absenteeism and fewer errors and defects. The report, "Greening the Building and the Bottom Line", cites improved heating and cooling in eight commercial buildings thanks to natural light. Installation of special skylights and-tall windows improved lighting and cut lighting costs by up to 75 percent. An unexpected effect was a 15-percent drop in employee absenteeism, as well as increased productivity and sales.

People living in northern cities that are overcast for long periods of time and receive little sunshine typically report depression. Birds housed continually indoors may also suffer from depression. Taking your wing-clipped bird outdoors for a bath in the sun is great for its plumage and its spirits. If you have the opportunity to see the plumage quality of birds housed outdoors that has access to rain and sunlight, you will be a believer.

Try to place your bird near a sunny window, but make sure it can move out of direct sunlight when it wants. A useful substitute may be a full-spectrum fluorescent bulb with the fixture close enough to the bird to provide the UV spectrum. Ideally, the bulb should be within a foot or two of the bird to provide benefits.

Remember that the capability of the bulb to produce UV does not last for the life of the bulb. The bulb can still be used for general lighting purposes after it is no longer producing full-spectrum light. Certainly, we must not forget the potential hazard of excessive UV exposure, such a skin cancer and eye disease.®

Bird Talk Magazine by Susan L. Clubb, D.V.M., DIP., AVBP - March 1996

---

All animals are dependent on light to some extent, but birds are particularly sensitive to it. Birds deprived of sunlight may develop a variety of problems, including poor nutrient absorption, vitamin D deficiency, feather plucking, and disruption of mating and breeding patterns.

Many bird owners place their pet's cage near a window or other light source, but that may not be enough to cure the problem, since glass can act as a filter, reflecting instead of transmitting certain portions of the spectrum.

Dr. John Ott's research into the light needs of people, plants and animals led to the invention of full-spectrum lighting, a term coined by Ott. Full-spectrum lighting recreates the light-environment birds and others have in the wild. The poultry industry has already discovered that the benefits of providing full-spectrum lighting include increased egg production, larger eggs with stronger shells, and healthier birds. Couldn't your bird benefit?

Pet bird keepers know that their companions need fresh air, proper foods and a constant supply of clean water in order to survive and thrive. But not everyone knows that birds need light, as well, for optimum health. Larges suppliers of Proper Lighting for birds are listed here:

Reprinted by Pretty Birds from Pet Business Inc.

Warning: Lighting: You may not be getting what you think you're buying.

Any incandescent bulb is fine for heat (for night time, you want dark light, such as the Nocturnal Light by Energy Savers Unlimited or a ceramic heating element). The technology (tungsten filament vs. the gases and coatings used in fluorescents) doesn't produce UVB, and only marginal UVA (which are the wavelengths in between UVB and visible light).

"Full spectrum" is a term used rather loosely. It can mean "produces UVB, UVA, visible light and infrared [the wavelengths longer than those in the spectrum we can see {visible light}] but the reality is that manufacturers of incandescents are calling their bulbs "full spectrum" to lull people into thinking they are getting UVB (and thus buying their product) when they are not. Incandescents are fine to use alone for room lighting, but birds require UVB. Also, birds from more northerly climates or colder temperature climates that do well with minimal UVB obtained from occasional exposure to natural sun thru windows, must have lighting used in conjunction with a UVB-producing fluorescents or lamps (not all fluorescents produce UVB or enough of it to do any good).

What's the difference between a WIDE Spectrum and a FULL Spectrum light?

Ahhhh....welcome to the Madison Avenue and the non-regulated pet product industry where accuracy never gets in the way of making product claims! Because there are no truth-in-advertising regulations covering pet products, manufactures can be as misleading as they like.

It used to be that 'full spectrum' lighting meant lights which produced both ultraviolet B, ultraviolet A and the full visible spectrum as well infrared heat. Once incandescent manufacturers figured out that people were being told to look for 'full spectrum' lighting, they started to market their wide spectrum (producing some, but not all of the visible wavelengths and no ultraviolet wavelengths) lights with 'full spectrum' in the ads and on packaging. Thus people are buying Chromalux, NeoWhite and "Full Spectrum" incandescent lights thought, incorrectly, that they are providing UVB, UVA and full visible wavelengths to their birds. In fact, incandescents are just producing, if they are putting out bright white light, only the visible spectrum; some which produce colored light, are not necessarily even producing the full visible spectrum, being corrected to increase or reduce certain parts of that spectrum.

Use Browser BACK Button

Pretty Birds: Copyright © 1997: Last Modified 07/13/00: Copyright Law and International Treaties protect these Web Site Pages. Warning: Reproduction or Distribution of these images, program, text or any portion of it, may result in severe civil and criminal penalties and will be prosecuted to the maximum extent possible under the law.