Have you noticed no matter how hard you try you always end up with more cocks than hens? I was talking to Phil Proctor recently and mentioned that I had read a report that suggested the use of full spectrum or daylight tubes in the aviary could increase the number of hens bred. Amazingly Phil said he had fitted these tubes in his aviary last year and had bred far greater hens than cocks this season. Coincidence or what? I though I’d investigate further!

As Budgerigar breeders we know that the length of the days influences mating and egg-laying activity and we provide artificial lighting to improve reproductive performance at the time we choose to breed. However, the artificial light that most of us use provides a poor substitute for sunlight. But did you know some fluorescent lights, particularly full-spectrum lights, do provide many of the stimulation and health benefits of unfiltered sunlight.

Birds synthesise vitamin D3 on their skin in the presence of ultraviolet radiation (UV) from sunlight or full-spectrum artificial lighting. This vitamin is essential in the metabolism of calcium. Calcium cannot be absorbed by the intestines nor can the bird's blood level be regulated without the presence of D3. Since we cannot depend only on diet to provide sufficient D3, UV light is essential to full calcium utilisation.

Creature Lighting

All surface dwelling creatures develop under the balance of light wavelengths emitted continuously by the sun. As they strike the earth's atmosphere, the length of the light waves is modified and some of the harmful rays are filtered out by the atmosphere. The greater the depth of atmosphere the rays go through, the more they are changed towards the red and infrared end of the visible spectrum. This is why the setting sun is so orange in color; its light must pass through hundreds of miles of atmosphere before it reaches our eyes.

When this normal balance of light in which birds evolved is altered by indoor artificial lighting, there are short and long term effects on the birds' lives, health and reproduction. Some of the more noticeable effects are known, but most are still unknown. For example, it can be physically proven that unbalanced light that strikes the human eye will result in an immediate reduction in muscle power and physical ability. This will also affect the muscle strength and endurance of Budgerigars and other birds.

There are a wide variety of artificial light bulbs and tubes available and most of these produce a balance of light wavelengths that is very different from that of natural sunlight. The standard light bulb, for example, produces light heavily in the red and invisible infrared wavelengths. Though we cannot see infrared radiation, we can feel it as heat. These bulbs do not emit any light in the ultraviolet wavelengths.

The commonly used fluorescent light tubes emit little or no light in red or infrared ranges of the spectrum and little or no ultraviolet. Those that are manufactured as full spectrum or daylight fluorescent tubes have a better balance of the light colors of the spectrum. The commercial tubes have a good balance of the light wavelengths that are nearest to the balance of natural sunlight but they are more expensive than the cost of the standard fluorescents.

Eggs For The First Time

A report published in the November 1971 illustrated the importance of full spectrum lighting in maintaining birds in captivity. The Bronx Zoo had for four years maintained a group of Tufted Puffins under artificial lights. During this time, there had been no breeding attempts. However, when the Zoo installed full-spectrum lighting, the puffins produced a fertile egg for the first time in captivity.

We know from research that light affects glandular development. We also know that under light stimulation, the pineal gland controls the synthesis and release of hormones and enzymes into the bloodstream. Perhaps most important, light received through the eye stimulates the pituitary gland. Since the pituitary gland is the master balance gland of the endocrine system and of the body, light in this indirect manner will influence all of the glands of the body.

Canary breeders have known for many years that the gradually lengthening days of spring are a primary factor in bringing their canaries into breeding condition. It has also been proven that the red wavelengths of the spectrum are a decisive influence in bringing birds into breeding condition. As a consequence, if you have budgies that are failing to come into breeding condition at the appropriate time, you might try installing a red light to increase the concentration of these wavelengths to which your birds are being exposed. Do this in addition to gradually lengthening the daylight hours for the birds.

The ultraviolet wavelengths are of particular importance for the health and breeding of cage birds. These invisible ultraviolet wavelengths are classified into two general groups, called the long wavelength ultraviolet and the short wavelength ultraviolet. Natural sunlight hitting the earth is rich in long wavelength ultraviolet, which is closer to visible light. It is also called near ultraviolet, since it is the nearest to the visible light. The long wavelength ultraviolet alone will cause pigment darkening in the skin (tanning) without burning. The commercial black lights give off light in the long wavelength range of ultraviolet. Ultra violet light will not pass through glass, but will pass through most clear plastics and quartz.

Formation of Vitamin D

The short wavelength ultraviolet, also called far ultraviolet, is farther away from visible light. It can be dangerous and is the form of ultraviolet that causes sunburn with overexposure. Yet this short-wave ultraviolet is not all bad, for it is this area of the ultraviolet wavelengths striking the skin that allows the formation of vitamin D. However, research has shown that many ultraviolet sources are not able to cause the formation of vitamin D on the skin, because the ultraviolet radiation is not intense enough. The sun's ultraviolet radiation has the necessary intensity for D synthesis. A sun lamp also emits ultraviolet radiation in the intensity required. However, other artificial lights do not emit radiation of sufficient intensity for D formation.

Another proven way in which ultraviolet light affects our birds is in the sex of the offspring of our breeding efforts. The long wavelength ultraviolet seems to be the primary factor in this influence. Experiments with fish, chinchillas, and other animals showed that the addition of full-spectrum lights in place of fluorescent tubes resulted in an enormous increase in the number of female offspring produced in breeding efforts under artificial light. Therefore, the frequent complaint that Budgerigars are producing a vast majority of males could be the result of indoor breeding under artificial lights that almost totally lack light in the ultraviolet wavelengths.

If you decide to change the lighting in your aviary to full spectrum please let me know. These tubes are available from www.sunriseaviculture.co.uk

©Terry A Tuxford 2004