Reprinted from the NCS Journal July/August 1999, Vol. XVI, No. 4
Lighting and Your Bird
by Patrick R. Thrush
Take a moment to think about your day, and where you have been.
Home, work, school, shopping, dining, and other activities. Now
consider the light in each of these environments. As we go about
our day to day business, very little thought is given to either the
quality or source of the light which makes our routine schedules
and activities possible. Simply said, it is just there.
The vast majority of the lighting we use bears little similarity
to the light of the sun. While useful for the tasks we need
artificial light to accomplish, common sources of illumination are
lacking in many areas of the spectrum which we consider balanced or
healthful. Humans, however, are very adaptable creatures. Given
proper nutrition and some exposure to the sun, health problems
because of lack of natural daylight are the exception rather than
the rule. Our bodies are not tied to the normal daily rhythms of
sunlight; we are not creatures whose metabolisms rely on photoperiod
for regulation.
This is not true for most animals, and especially birds. In the
wild, animals rely on the cycling of the sun, and the seasons to
adjust their biological clocks and metabolism. It is the sun, and
changes in the quality of light and length of the day which set the
stage for breeding, migration, molting, and daily behavior
patterns. Birds have a highly developed sense of light. In humans,
we perceive light through our eyes. Our feathered friends have an
additional way of interpreting light conditions, a special gland
which surrounds the eye.
This organ, called the Harderian Gland, works in combination with
the light a bird receives through the eye, affecting both the pineal
and pituitary glands within the brain. These two brain glands are
what regulates the growth and development of warm blooded animals.
Variations in the intensity and color composition of light serve as
triggers to prepare the bird for seasonal changes, and breeding
behaviors. As such, light acts as an adjustment mechanism to fine
tune the bird’s circadian (daily) clock.
A second consideration of sunlight concerns the health of the
animal. Ultraviolet radiation works with the natural immune system,
strengthening it to protect the bird against pathogens. Again, a
twofold process occurs. The ultraviolet in and of itself serves to
reduce surface pathogens (germs and bacteria) on the bird. In
addition, the balance of light bolsters the psychological condition
of an animal, meaning that it biologically “knows” the natural
state of its environment, and engages in activities which are part
of the rhythm world it inhabits.
Many animals also use the middle ranges of ultraviolet light to
assist in synthesizing Vitamin D. In this process, the liver
manufactures a chemical known as 'precursor D'
(7-dehydrocholesterol) a "good" cholesterol. This substance is
released into the bloodstream, where exposed to the middle range of
UV through surface skin and retina, becomes "previtamin D". This is
sometimes confused with D2 (calciferol), a form of the vitamin which
is found in plant sources.
The natural temperature of an organism then rearranges this
substance further, forming a weak D3, or cholecalciferol. This is
what is generally available as a dietary supplement in bird
pellets. To become fully active as Vitamin D, the liver and the
kidneys make other changes in the chemical, resulting in true
Vitamin D3 (1,25-dihydroxycholecalciferol). In any warm blooded
animal, once a source of calciferol or cholecalciferol is
introduced, UV of any sort no longer plays a role in the synthesis.
This is evidenced by animals who are nocturnal or burrowing and
receive no UV exposure, but acquire proper levels of Vitamin D from
dietary sources.
The visual capabilities of birds are also quite different from
the human range. We are able to see three different primary color
ranges. This is referred to as trichromatic vision. In the bird,
there is still another dimension. Birds can see well into the near
ultraviolet range. It is as if a fourth primary color was presented
to us. This is termed tetrachromatic vision. The addition of
ultraviolet vision gives many perspectives of view that enable the
bird to differentiate other birds, foods, predators, and the very
direction that the light is traveling from. There is some research
which indicates that this perception is used in the navigation
system of birds.
We know then, that sunlight fulfills a four-fold purpose in the
life of a bird: it regulates the metabolic clock and gives
perception of season; its full range is almost completely used for
vision; it assists in the health and sense of well being of the
animal; and it provides necessary vitamin support for bone and
physical development. It is a combination of these factors which
enable the bird to survive and reproduce others of its kind in the
most effective and natural fashion. This is the system that is
imprinted into the genetic makeup of birds.
Let us now consider the situation of the captive bird. If it is
in an outdoor aviary, then no further discussion of the need for
artificial lighting exists. The reality is that a great percentage
of captive birds are housed in indoor environments, subject to the
same poor substitute for sunlight that we humans have become
accustomed to. As such, the factors discussed in the previous
paragraph are missing in the life of the bird. To make for as
natural and healthful as possible an environment, the addition of
artificial lighting becomes necessary. We now enter the somewhat
confusing world of full spectrum (FS) lighting.
Contrary to various claims, only a fluorescent device can be full
spectrum. The basic physics of incandescent bulbs prohibit them
from producing a wide enough spectral range to duplicate sunlight.
Certain types of bulb, termed neodymium after the rare earth they
are coated with, claim to be full spectrum. They are not. These
devices merely filter out the lower red wavelengths, appearing to
the human eye to ‘whiten’ the light. In decreasing these lower
ranges, crucial components which are necessary to breeding and
cellular activity are not provided. These lamps are neither
healthful or appropriate for your birds.
For a fluorescent lamp to be properly termed full spectrum it
must have a CRI (color rendition index) of greater than 90, and a
Color Temperature of greater than 5000K. Below is a chart which
shows the more common FS lamps appropriate for avicultural use:
| TABLE 1 - FLUORESCENT
LAMPS FOR AVIAN USE |
| Lamp |
Cost Factor |
Color Temperature |
CRI |
Manufacturer |
| SPECIALTY FULL
SPECTRUM |
| TL950 Series |
$$ |
5000 K |
98 |
Philips Lighting |
| bioLIGHT LT48BE8 |
$$$ |
5000 K |
98 |
OTT bioLightsystems |
| Lumichrome 1XC |
$$ |
5000 K |
96 |
Lumiram |
| Lumichrome 1XX |
$$$ |
6500 K |
96 |
Lumiram |
| GENERAL FULL
SPECTRUM |
| Colortone 50 |
$ |
5000 K |
92 |
Philips Lighting |
| Vita Lite Plus |
$$ |
5500 K |
91 |
Duro-Test |
| Chroma 50 |
$ |
5000 K |
90 |
General Electric |
Any of these lamps may be used in either a 24" or 48" length. It
is recommended to install a lamp with a CRI of 92 or greater in
order to achieve the longest period of use between tube
change-outs. Due to the process of ageing, lamps need be changed
out approximately every 9000 hours (two years) of use for most
devices. Some 24" devices (such as the Chroma 50) must be changed
out every year. Shifts within the output of the device have skewed
them considerably away from their initial parameters. These old
lamps are not useless, however. They may be used for quite some
time in general home and shop illumination fixtures.
Whatever length lamp you use, it should always be in pairs.
Single source fixtures simply do not provide enough light output to
be truly beneficial to your bird. Whenever possible, mounting from
the ceiling is the best and most natural method. Only mount from
the sides when it is impossible due to cage construction to suspend
the fixture overhead. In addition, the fixture optimally can be
suspended 1'-1½’ from the top of the cage. The concept of placing
it closer to the cage is an artifact of reptile keeping, and is
unnecessary and possibly detrimental for the captive bird.
Overhead suspension accomplishes two things. First, the light is
directed downward, as it would appear in the outdoors. This ensures
that your bird perceives the light as coming from a natural
direction. In this manner, light direction cues are delivered
consistent with what the avian brain expects to experience. It also
makes for a good saturation of light, both visible and invisible
into the cage area. Objects are illuminated equally in this
fashion, and are placed into proper visual perspective. Secondly,
it is easier to control the intensity of light reaching cage areas.
Too bright a light is not a good thing. If the area looks over-lit,
it probably is. The same rules of visual comfort that apply to
humans apply to your bird. Use them.
The final basic consideration of artificial lighting concerns
photoperiod. It has already been noted that photoperiod adjusts the
biological clock within the bird. The need for this pattern is not
diminished when birds are kept indoors, or after successive
generations of breeding. Therefore, providing your bird with a
regular schedule of light is of great importance. This is why all
lighting should be connected to a timer system. Such a setup
guarantees that your bird receives the proper amount of light every
day. Most keepers will note that after several weeks on a timer,
the bird is able to anticipate when the light will come on, and when
it will go off.
On the average, birds will require between 10-14 hours of light
per day. A median for non-breeders is 12 hours. It is always best
to set the timer to turn the lamp on about an hour after sunrise,
and shut it off about an hour before nightfall. This enables your
bird to “get up to speed” in the morning, and “wind down” at night.
It also more closely matches the graduation of light throughout the
day as experienced naturally. Of course, the timer settings must be
adjusted for seasonal changes in sunrise and sunset, and also for
daylight savings time. If covering your bird, it is recommended to
use a thin material which will transmit part of the light when it
comes on. Covers should be removed soon after this time, and placed
on the cage only after the light has turned off.
While most full spectrum lighting supplies sufficient middle
range ultraviolet for Vitamin D synthesis, much of this wavelength
is lost as the device ages. It becomes of more importance from this
perspective to ensure that your bird is receiving a quality diet
which supplements Vitamin D intake. This may be confirmed by
finding either calciferol or cholecalciferol listed in the
ingredient list of packaged or pelletized foods. Provision of green
vegetables and fish oils will assist in this process. All the
lighting in the world will not offset the effect of poor diet. Do
not expect any lighting source to uniformly and completely meet your
bird’s Vitamin D needs.
When first using full spectrum, the amount of light produced may
not seem “enough” to you when applied as directed. Beware comparing
this illumination to what would be expected from a standard
flourescent tube. We humans do not see as well into the blue and
violet range as we possibly could, or nearly as well as our birds
can. Because full spectrum lighting has a well distributed blue
output, it appears as an ‘optical illusion’ to us of decreased
brightness when using these tubes. You will note however that
colors are more vivid, visual acuity increased, and eye fatigue
reduced. Be aware that your bird sees this environment much
brighter than you do.
Your bird depends on you for the majority of its needs, both
physical and mental. By following the recommendations given in this
article, you can rest assured that you are doing the very best to
provide your companion with a balanced lighting environment.
Research indicates that light plays an important role in the
longevity of captive birds. In practicing sound lighting
management, you are working toward spending many more enjoyable and
healthy years in the company of your feathered friend.
