Do Lighting CRI Ratings Help Birds & What the Heck are They?

Do Lighting CRI Ratings Help Birds & What the Heck are They?

Last Updated on by Mitch Rezman


I wanted to inquire about the three bulbs I purchased that were delivered today.
They are not the same bulbs that are shown in the photo and I’m not seeing a CRI on the bulb itself to be able to confirm that these are full spectrum.
I tried doing a google search of the product and from what I found, these bulbs have a CRI of only 81 (not full spectrum).
The bulbs were not delivered in a product box, they were sitting in a plastic container and wrapped with packing materials, so again I can’t confirm if I was shipped the incorrect bulbs.
Can someone please look into this for me? 
Caitlin D.

Hi Caitlin


We appreciate that you paid your due diligence on the subject of CRI.


To be clear 10 years of working with veterinarians, research organizations and veterinary colleges have taught us that CRI has no value to a bird’s eyes (specifically the pineal gland).


CRI arbitrarily defines the “color” of light but does not determine if the light source is full-spectrum or not.


That is determined by the Kelvin temperature of light. 


5000 to 6500 K is considered “full-spectrum lighting.”


The fundamental information that birds rely on from light ~ is its cycle.


Because birds have 100 million years of instinctual expectations coming from equatorial regions of the earth having roughly 12 hours of light and 12 hours of darkness, a cycle other than that will stress the bird out and trigger things like bad hormonal behavior, feather plucking, and prolific egg-laying.


As for the bulb you received is slightly different from the image on the website all I can do is apologize.


Much like the empty spaces you see in grocery stores today keeping one of our best selling items in stock has been a challenge.


Thus we have brought in full spectrum CFL light bulbs from four vendors in the last six weeks.


Full Spectrum Economy Daylight Bulb with Clamp Light & Timer















Full Spectrum Economy Daylight Bulb with Clamp Light & Timer


Editor’s note: We believe LED lighting stress birds out due to their flicker fusion rate


We temporarily halted posting new pictures because we don’t know where the next bulbs are coming from.


We have 10 birds in five primary cages all with full-spectrum bulbs some different from the others.

Three clamp on lights over budgie aviary

3 Full Spectrum Lights Over Windy City Parrot’s Budgie Aviary


Our budgie aviary which at one time had a population of 10 (four males ~ six females) has only seen one egg produced in four years.


We have been pet bird care advocates since 1993 and would never provide a product that is substandard or would harm a bird.


Here I offer 240 blog posts on avian lighting written primarily by me but some veterinarians and university researchers have added their two cents as they were written before the coin shortage.


Lastly, (almost) this communication came in from one of our readers last week:


Light therapy.

This is more a thank you than a comment. Your light therapy suggestion is making a world of difference for my wife’s Goffins cockatoo Buddy. He continually plucked chest feathers until about 2 months ago when we started using a daylight light placed close to his enclosure. His chest is full now and he looks great. Thank you so much for that article.

Stephen T


Stay safe,





double full spectrum l;ighting over cockatiels playtop birdcage

Our Cockatiel, Barney With 2 Full Spectrum Lights Over His Playtop Bird Cage


Here is some additional information you will find useful to ramping up your personal pet bird lighting knowledgebase:


CRI, TM-30-15… Wait, What? 


So, what exactly is CRI? CRI stands for color rendering index—it’s a scale of measurement. It’s a light source’s ability to depict object colors “realistically” or “naturally” when compared to a familiar reference source, such as incandescent light or daylight. When a manufacturer publishes a CRI measurement, they communicate to their consumers how closely or accurately this lamp compares to its incandescent or halogen counterparts, or even natural daylight.


CRI was established in 1965 and had a major revision in 1974. CRI is based on 8 color samples, and uses a fidelity metric compared to a reference lamp. This type of measurement has worked well for the last three decades, but due to the advancement of LED, CRI leaves out quite a bit of information that can help a lighting designer make the best lamp choice. CRI is good, but it does not tell the whole story. Read More:


Full Spectrum Lighting for 2 Birdcages at Windy City Parrot ~ Video

A color rendering index (CRI) is a quantitative measure of the ability of a light source to reveal the colors of various objects faithfully in comparison with an ideal or natural light source. Light sources with a high CRI are desirable in color-critical applications such as neonatal care and art restoration. 

The Kelvin definition is “the SI base unit of thermodynamic temperature, equal in magnitude to the degree Celsius.” Scientific jargon aside, Kelvin is used in lighting to measure the color temperature of a particular light bulb. And in short, the higher the Kelvin rating (expressed in K), the whiter the light will be.

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