The Importance of Light to Your Bird

by Theresa Jordan
(from "The Quaker's Nest" Vol. I / Issue I, 1998)

Birds, as well as humans and other living organisms, are dependant on light for good health and even survival. Yet natural sunlight is one of those things that we just naturally take for granted. One of the most important biochemical reactions to occur on our planet is photosynthesis, which is nature's way of using plants to create food, not only for the plants themselves but for all other organisms. Sunlight plays a critical part in this creation, fueling the actual process of photosynthesis.

Of all animals in existence today, birds are one of the most profoundly affected by light. They have survived and evolved for millions of years relying on the full spectrum of light created by the seasonal cycles of the sun. They rely on sensory input from their eyes possibly more than any other species. And light has a tremendous influence on their growth, metabolism, reproduction, and behavior as well.

Young quakers, by their very age, are at the most important stage of their growth and development cycle. Nutrition at this point is essential. And one of the most critically important minerals to a bird's overall health and development is calcium. Calcium promotes strong bones as well as the maintenance of many physiological functions. Without calcium, birds can suffer spontaneous fractures, which may cripple them for life.

Unfortunately, calcium cannot be absorbed by the intestines, nor can its level be regulated, without the presence of Vitamin D3. Vitamin D3 can be obtained in 2 ways: through the diet; and via a process in the skin known as synthesis. The process of synthesis requires ultraviolet radiation of a specific wavelength. The most common source of this radiation is, of course, sunlight. So, in a nutshell, your quaker needs sunlight (or full-spectrum artificial light) in order for his body to absorb calcium. This essential ultraviolet radiation is filtered out by normal window glass; hence, light coming through a window in your home cannot stimulate the production of of vitamin D3 in your bird's body.

Sexual behavior, egg production, the development of the gonads in the male.......... all of these factors and more are affected by light. Egg production can be increased by artificially creating longer periods of light, simulating natural seasonal light cycles. Altering light in a cyclic pattern can also affect sexual development; and interfere with sexual performance.

The timing of the reproductive cycle is governed by the length of the daylight hours --- longer days stimulate reproductive organs and sexual behavior. In most species, the breeding season has a linear relationship with the annual cycle in day length, with the breeding season coming to a close while daylight hours are still increasing.

Light also affects molting. Birds in their natural habitat usually molt twice a year, in a definitive pattern; ie, molting feathers on the left side of the body will correlate with feathers on the right side of the body. In some cases birds will molt continuously at a low level. Molting can be identified by the presence of "blood feathers", which are new feathers emerging to take the place of the molted ones. These feathers have a blood supply and will be encapsulated in a white thick sheath, known as keratin (protein). When the feathers mature completely, the blood supply will dry up and the sheath will slowly flake away, exposing the new feather.

Your bird's behavior is also affected by light. Intensity of light dictates the time at which birds go to roost, and when they emerge in the morning. Diurnal species depend on daytime light intensity to accomplish foraging and hunting. In cases of display behavior, light is needed for flaunting plumage, in order for males to attract females. And this in itself also has an effect on reproduction; if the highly ritualized displays and subsequent courtships were to be adversely affected, birds would be unable to mate and reproduce.

While in some climates it's not feasible to keep your feathered friend outdoors, this does not diminish the importance of light. As an alternative, full-spectrum artificial lights have been developed to simulate natural sunlight. These lights provide the full-color and balanced ultraviolet spectrum of natural outdoor light, at a reasonable cost. The most popular type is Vita-Lite, a general purpose florescent lamp which can be purchased at most hardware stores. Changing the bulbs routinely every 2 years ensures maximum effectiveness.

While this is generally a broad explanation of the importance of light, there are numerous individual variations in avian responses to light. It is these individual variations, along with their responses, that allow us, in awe, to view the beauty and grace that we witness in our skies as well as in our homes.

References.
Bird Talk Magazine, 1991.

The Quaker's Nest || Quaker Information Center