Full Spectrum Lighting

This is a very complex subject, and honestly one that I am not fully qualified to discuss. However, I will attempt to share with you what I have learned, from articles as well as from people in the online avian community.

Our birds need Vitamin D – specifically D3. It is a crucial component in the calcium-phosphorus-D triangle. A problem, whether too much or too little, of any of these, can cause issues with the other two. Not only does it help with calcium metabolism, it is also important to cellular function, bone mineralization, and helps regulate other body functions. Vitamin D3 is manufactured by the skin; thus it is not found in plant based sources (aside from lichen, I’ve recently learned). It can be found in egg yolks, beef liver, fish oil, and a few other sources. Because D3 is 30-40 times more potent than D2, it is considered insufficient in the diet, as a bird would need to eat more than they are physically able to in order to make up the deficit.


The best and easiest way to get D3 is access to unfiltered sunlight. All modern windows are manufactured to filter out UV light, and UVB in particular is needed for our bodies to make this vitamin, so just having the cage in front of the window actually provides little to no benefit for that. In areas of the world that have weather that permits supervised, safe access to the outdoors year round a few times a week likely need no supplementation at all. However, those of us that live far from the equator like myself in Northern Michigan, 6+ months of the year I am not able to take my birds outside, thus creating a gap in their nutrition.

So how to combat this? Two main ways that you will hear are pellets (which most contain a synthetic or natural form of D3), or full spectrum artificial light. Neither is perfect, but I will always opt for pellets.

The reasoning is this. In my research, and that of those I’ve read, is that there is a couple of issues.

  • UVB is what aids in Vitamin D3 production, and yet the levels of UVB in bulbs claiming to offer it are inconsistent at best
  • UVB has only been detected by meters at extremely close (6-12 inches away) proximity, which can be dangerous to birds’ eyes
  • UVB degrades quickly, meaning that the bulb only emits those waves for up to 6 months. So while the bulb may continue to offer light, it does not offer the light type needed for D3 production.
  • Long term exposure to UV lights has been shown to cause cataracts in birds, reptiles, and rats.

If  you would like to learn more about this, please see below some of the most compelling thoughts on this matter are.

Dr. Scott Echols, DVM, said this on his Facebook group, “Nutrition for Pets“:

Very few UV bulb have been critically tested. The few that have suggest the quality is highly variable (within the same product). In some climates, UV bulbs are the only (and distant second) option for captive animals (over sunlight). Until I see some more promising studies, I will have a hard time recommending UV lights over natural sunlight.

An interesting article that Dr. Echols paraphrased showed some insight into tortoises and Vitamin D3, which while not exactly a bird, we can assume that at least some of what is true for reptiles is true for birds:

Today I received the latest copy of American Journal of Veterinary Research (AJVR). While I am always excited to receive such great literary works, it was the article on vitamin D and Hermann’s tortoises that caught my attention….

Three groups of tortoises were studied:1 group was kept outside, 1 group indoors with a UVB mercury vapor lamp and the last group indoors with a UVB flourescent light. All other factors (temperature, time of year, diet, etc) were kept the same. The lamp and flourescent light were used as directed by the manufacturer.

Plasma vitamin D3 levels were measured at the start and 35 days into the study. As expected, the natural sunlight group maintained their vitamin D levels throughout the study. However, the UVB lamp and flourescent light tortoises’ vitamin D levels dropped precipitously in just 35 days.

The author’s concluded that at least Hermann’s tortoises need sunlight equivalent to a latitude of their natural range.

This is just another study in a series of recently puplished papers showing the importance of unfiltered sunlight and blood vitamin D levels in captive reptiles.

Similar such studies are lacking in most other animals (except humans). However, years of clinical experience supports that many animals need some direct exposure to sun in order to maintain normal vitamin D levels.

Here is a post from LaSelva at Avian Avenue that breaks down some of what we know about UV lighting and his take on what the problem with the bulbs are:

There are two categories of fluorescent full spectrum:

a) General Illumination. “A general illumination lamp that may be properly termed full spectrum has a CRI (color rendition index) of greater than 90, and a Color Temperature of greater than 5000K. These devices are not intended as a source of UV irradiation, but do produce small amounts of UVA (near-range ultraviolet) as a byproduct of their operation.”

These are the fluorescent full spectrum bulbs and ballasts available at Home Depot, etc. They are not UVA or UVB (mid-range ultraviolet light) which is involved in vitamin D synthesis. Again, that’s ok because our birds do not need bulbs for vitamin D synthesis…..

“Most pelletized diets, and a balanced natural diet contain cholecalciferol or calciferol, a precursor to Vitamin D3. The presence of UVB is not necessary for birds to convert this form to usable and sufficient levels of Vitamin D. “

But, if this is your goal or purpose in lighting then the only way to achieve this is through a fluorescent UVA/UVB bulb.

b) Specialty Illumination. These are UVA/UVB, marketed as “Avian Bulbs.” They are “Specialty illumination devices, such as the pet series (Vitalite, et al.) and tubes for seasonal affective disorder (Ott, et al.) contain varying amounts of ultraviolet light in the near (UVA) and possibly middle (UVB) ranges in addition to meeting the general illumination criteria. ”

Here are some issues with these bulbs:

1)“UVB irradiance is weak, is unbalanced negatively in relation to natural sunlight levels, and does not travel as far from the lamp as visible light. With this in mind, the popular concept has been to place the lighting source as close as possible to the bird to achieve useful exposure for natural pre-vitamin D (cholecalciferol) synthesis “

“When Dr. John Ott was researching the effects of light on various plants and animals, it became quickly apparent that imbalances in the spectrum of light delivered could affect the organism in a variety of ways. Applying this research to humans, imbalances in lighting have been shown to cause depression, lethargy, decreased immune response, and in some cases, agitation and aggressive behaviors. Each factor noted in the human species has a direct equivalent for animals of all species. ”

2) UVB output degrades quickly….

”efficiency will have degraded after six months to where the device is generally useless in playing a part in the Vitamin D synthesis process”

But the dangers of a bulb kept so close to your bird remain…..

3) “Another problem concerns avian visual and endocrine disturbances from the visible and UVA output of the lamp at close range. Improper lighting can bring on varied health problems; behavioral and breeding disorders which are often attributed to other sources. These symptoms and problems include but are not limited to: lack of strength and endurance; feather and toe picking; restlessness and agitation; decreased immune response; abnormal sex ratios in breeder situations. Therefore, how could one even consider an arbitrary close distance appropriate for the health and environmental comfort of their bird? “

Stronger UVB output bulbs don’t help the degrading and weak output factor but make matters worse:

“Concentrations of UVB in fluorescent tubes can be increased, but due to the amount of barium based phosphors involved, these devices are no longer lamps which can produce a suitable visible spectrum. When manufactured in this manner, the lamp becomes either a reptile series lamp or tanning (erythemal) device, and must necessarily be regulated or controlled in exposure to prevent damage to humans and animals. The effective life span of these devices is also short, as noted by the previous discussion. Unnecessarily increasing the UVA/UVB to peak levels may cause problems to present themselves in the form of retinal degeneration, cataract formation, and calcium/bone disorders. “

A follow up post from Stormcloud (speaking as Einstein!) further elaborates.

LaSelva is quite correct in pointing out zat zie globes, or bulbs, vitch ever is your preference to describe zem, are quite veek regarding zear output of both UVA & UVB category light spectrums. Even if vee use zie reflector specified by zie manufacturer to concentrate light output to a given focal point zie light vood have to be positioned quite close to zie bird. Vee are talking about a distance of 150-200 millimaters, or 6 to 8 inches, for zie light to have zie desired effect. If vee need to have zie light positioned zat close to zie bird zen vee are probably risking eye damage, zuch as catarats, to zie bird. Zear are many variables at play here, such as vear zie bird is positioned in zie cage. Sometimes he vill be at zie top, and sometimes he vill be at zie bottom, but vee do know zat birds tend to perch in a higher place zan a lower place as zay feel safer zear. Since your cage is very tall at 1800 millimaters (6 foot), vee shall assume zat your bird is positioned at an average height of 1200 millimaters (4 foot). Vee shall also assume zat zie bracket holding zie reflector keeps zie light mounted at a distance of 100 millimaters (4 inches) above zie cage top and zat zie light need to be vissin 175mm millimaters (7 inches) of zie bird to have zie optimum effect. So vee can determine from zis information zat your bird vill be at an average distance of 28 inches from a light zat he needs to be vissin 7 inches of to gain zie optimum benefit. To solve “Dana’s Dilemma” vee shall use my Inverse Square Law for zie Intensity of Light. Zis law of physics states zat if vee double zie distance of zie light source from a given point zat its intensity vill drop to a quarter of vot it voz originally (2 squared equals 4) and if vee triple zie distance zen zie intensity vill drop to vun ninth (3 squared equals 9). In “Dana’s Dilemma” vee are actually quadruple zie distance (28 inches divided by 7 inches = 4) and zearfore zie intensity drops to vun sixteenth (4 squared = 16). From zis vee can deduce zat Dana vill need to mount sixteen lights from zie top of zie cage to solve her Dilemma. I am sinking zat zuch a vast lighting array vould consume a large volume of electricity, but at least Dana vould have a magnificent new chandelier in her dining room.

The reason synthetic vitamins, such as D and D3 are used in pellets is that they are molecularly stable, usually for a period of at least twelve months, before they start to degrade or oxidise. The simple reality is that you are far more likely to get the required of amounts of Vitamin D & D3 into your birds using a high quality pellet, such as Roudybush or Harrison’s than you are using bulbs.

Sarah (macawnutz) did some personal research on bulbs as well, including what the manufacturers had to say:

I have been researching this for the last few months. I have read and re read every post on AA for the last few years and also read and re read many articles about the subject. While MUCH of it is still over my head and I still have MUCH to learn I have a few questions and statistics I would like to post.

The reason I am researching this is because I wanted to change over all my home fixtures to full spectrum CFL’s. Home fixtures meaning they will not be close enough to have benefits of UVB (and I know there is debate on if there are benefits) But I wanted them to at least visually benefit. I have been researching many of the AA recommended brands and thought I should share. Some of the companies I have emailed have not replied yet but as they do I will update this list.

Now most of us look for a Kelvin rating of 5000-5500 and a high CRI rating.

full spectrum lighting,full spectrum lights, full spectrum cfl’s,full spectrum lighting for the home or office, lumichrome full spectrum lighting chromalux full spectrum light bulbs, energy efficient light bulbs, compact fluorescent bulbs, cfl”s 93CRI, 5000K UVA 3%, UVB .05%

Full Spectrum 15w light bulb by FeatherBrite 5500k, 91 CRI, UVA 4%, UVB .05%

Full Spectrum Light Bulbs | Fluorescent Bulbs | Incandescent Bulbs (bluemax 20watt spiral ratings but uv outputs for all bulbs and tubes) 5500k 93CRI, The purpose of Ultralux, Paralite and BlueMax products is to replicate natural sunlight at noontime without any UV emission. We use a patented blend 3-6 color phosphors to achieve a visible color spectrum that is very close to the noontime visible color spectrum. For there to be any UV emission special phosphors must be included within the phosphor blend. Although some UV exposure can have some positive effects, we at FSS believe one should receive this from sunlight and not from a simulated light source that is used at close proximity and for extended periods of time. We do not include any of these UV phosphors and our spectral chart shows that the produced wavelengths are 400-750nm. UV wavelengths are below the 350nm range and infrared wavelengths (heat) are above 750nm.

AvianSun 7100k,CRI 93, UVA 3% UVB 5%
Thank you for contacting us. The UVA is 30 % from the Avian sun bulb and the CRI is 93 and the color Temp (K) is 7100. Please let me know if you have any further questions.

Philips 209056 F32T8/TL950 Straight T8 Fluorescent Tube Light Bulb at eLightBulbs.com 5500K, 98CRI

Now I have seen many people recommend the phillips tubes. They have yet to respond to my emails but I have a feeling they will not have a decent UV output. I guess my first question is, without a decent UV output does it even benefit them visually? Other than I guess clarity of light. Would they not be seeing in their spectrum of light without the UV outputs?

The other recommended avian light, Avian sun 5.0 I was shocked at 7100K. I wondered why they did not list any statistics other than UVB. This would pretty much confirm what I have read that the avian sun light is nothing more than a repackaged reptile bulb. Reptile lights from what I have seen always have a high Kelvin rating.

She did end up getting a response about the Philips tubes, too:

Here was phillips answer

I am emailing to find out about your F32T8/TL950 Fluorescent tubes.
I see that they are 5000k and 98 CRI. Could you tell me the UVA and UVB outputs on them if any?

Dear Customer,

Thank you for contacting Philips Lighting Customer Care.
I apologize for the delay in our response, I have checked with our Product Manager and have received the following response:
Lamp Type UV-FDA1 (W/cm^2) UV-FDA2 (W/cm^2) UV-FDA3 (W/cm^2)
F32T8/TL950 3.79E-06 7.13E-07 1.46E-08

Translation….. No UV outputs

Overall, from what I’ve been able to read and discern for myself, is that UV bulbs with the intent to supply D3 are an expense that should be skipped. They are costly, must be replaced often, and actually can do more harm than good if used per the manufacturers recommendations. Get your birds outside as much as possible to soak up the “Sunshine Vitamin” and if you can’t regularly do that, speak to your vet about what the best option for supplementation is.


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