No KiwiBird, Leopard Geckos specifically do not need any type of UVB light, only a heat source, either a UVA/heat bulb/light, or a heat-mat underneath their substrate, such as carpeting...I don't like using heat-rocks, a lot of people do, but a lot of reptiles require that their heat comes from above them, and they end-up with thermal burns on their bellies from laying on heat rocks.
***Let me explain why captive, pet birds do not NEED or REQUIRE any artificial UVB lighting...Just keep in-mind that there are many reptiles and amphibians that will not survive without a proper-strength UVB light on every day, for hours and hours a day; You above got lucky as you got a Leopard Gecko, and they are one of the reptile species that don't need a UVB light to survive, however, had you gotten a reptile that does need a UVB light to survive, such as a Bearded Dragon, he would have quickly developed Metabolic Bone Disease, and died a slow, agonizing death after suffering for months to years first...So it's extremely important that you absolutely make sure that whatever reptile/amphibian that you are deciding to buy/bring home as a pet doesn't need a UVB light to simply survive, and if they do then you absolutely must not only buy a UVB bulb and a fixture for it, but you must make sure that you're buying the correct type/strength/UVB output for that particular creature that you're buying...
***Now, back to birds...I didn't get to post this yesterday as I got busy...However, I believe it's important to not only know what type of UVB light you should and shouldn't buy for whatever type of pet you have, but I also believe that it's extremely important that you understand WHY OR WHY NOT your specific pet needs or does not need any type of artificial lighting. In addition, you need to know that if you make the decision to put your pet under an artificial light of some kind, even if they don't need/require one, that you make sure that an artificial light isn't going to do any harm to your pet...For example, buying a Coil/Spiral UVB bulb and putting it over ANY SPECIES OF PET, whether they need and UVB light to live or not, will eventually result in chronic eye infections (Photoconjunctivitis), eye damage, blindness, skin damage/burns, skin cancer, etc. The fact that any brand/strength of Coil/Spiral UVB bulb emits harmful light rays as a by-product of the manufacturing process used to make them is very widely known in the Reptile/Amphibian Community, but unfortunately is not at all known in the Avian community; the same goes for the fact that any brand/strength of Compact UVB bulb (regular light bulb shape) emits extremely weak and non-beneficial/non-adequate UVB light is also widely known in the Reptile and Amphibian Community, but again, not at all known in the Avian Community. With more and more bird owners insisting on putting their birds/parrots under artificial UVB lights, regardless of whether it's beneficial for them or not, or harmful to them or not, I believe the Avian Community needs to start being made aware of these facts as well...
***Something I forgot to mention in my post yesterday: If you want to use a UVB bulb that fits into regular light bulb shape lamp/fixture instead of buying UVB tubes and tube fixtures, you'll find if you do any research in the Reptile Community that they use Mercury Vapor Bulbs (MBV), which are combination-bulbs that fit into regular light bulb sockets. MVB's are combination bulbs that emit both UVB light AND UVA light/heat. So if you are someone who has your bird under some kind of artificial heating as well as a UVB light, then buying a high-quality MVB is the best and safest option you can buy. The best brands of MVB are MegaRay and Arcadia; PowerSun's (ZooMed brand of MVB's) are also decent; Please stay away from Sun-Glo MVB's (Exo-Terra's MVB brand), especially if you have a Bearded Dragon, as they are a beautiful MVB, however the amount of UVB light they emit is extremely weak, and Dragons who are under Sun-Glo MVB's regularly develop Metabolic Bone Disease (MBD).
Now, back to birds and why they don't need nor require any type of artificial lighting, specifically UVB lighting. (There are several different types of "bird lights" sold on the market, the most common "bird lights" are UVB lights; any other type of "bird light", such as a UVA/heat "light" is completely unnecessary and harmful to your bird, if your bird is in a room that is cold, and you want to use a "bulb" type of extra heating, then please just buy a Ceramic Heat Emitting Bulb (CHE), which screws into any regular light bulb socket or lamp, but only emits heat and no light rays)...Some of the "bird lights" are also UVD lights, which is ridiculously unnecessary for most living creatures; since UVB lights are the ones that are most-commonly purchased as "bird-lights", I'll stick to talking about them...
As pointed-out above by KiwiBird, there are some reptiles and amphibians who do not require/need a UVB light in order to survive, they only need an extra heat-source. However, there are MANY different species of both Reptiles and Amphibians cannot survive without getting adequate UVB light every single day, and who will quickly develop deficiency-diseases from not being under an adequate UVB light every day, and eventually they will die...The most common pet Reptile that absolutely must be under a proper, safe, adequate UVB light every single day for at least 11-12 hours a day is the Bearded Dragon...But why do certain reptiles and amphibians require an added UVB light to survive?
****Certain species of reptiles and amphibians (and other creatures/living organisms) require getting at least 2-3 hours each and every day of natural, direct sunlight (outside, not through a window, as glass and clear plastic block ALL UVB rays!!!) in order for their bodies to be able to manufacture Vitamin D3. Certain living creatures, such as Bearded Dragons, must either ingest/eat or have their bodies manufacture ENORMOUS AMOUNTS OF VITAMIN D3 each and every day, as their bodies cannot absorb, process, nor use ANY of the Calcium that they take-in from their food or from an extra Calcium supplement/powder without these enormous amounts of Vitamin D3. It's impossible for these living creatures, such as Bearded Dragons, to simply ingest/eat the extremely high amount of Vitamin D3 in their food each day that their bodies require in order to properly absorb/process/use any of the Calcium that they get from their food and Calcium supplements. So, because their bodies require a very large amount of Vitamin D3 in order to absorb and process the amount of Calcium that their bodies require, and it's impossible for them to eat/take-in that amount of Vitamin D3 from their diets/vitamin supplements, their bodies are designed/created to be able to directly manufacture large amounts of Vitamin D3 from absorbing adequate amounts of UVB light. Without these living creatures getting absorbing enough UVB light each day, they cannot and will not manufacture near enough Vitamin D3 to allow their bodies to absorb/use Calcium that they are ingesting from their food and any Calcium supplements, and any and all Calcium that they do take-in from their food or Calcium supplements is simply excreted from their bodies in the urates that are excreted in their feces. So what happens with these creatures if they don't absorb adequate UVB light each and every day is that they make no Vitamin D3, therefore they cannot absorb any of the Calcium that they eat in their food and supplements, their bodies simply excrete all of the Calcium that they take-in in their food and Calcium supplements in their feces (in the urates), and as a result their bodies start leeching all of the Calcium that they need out of their bones, ligaments, tendons, etc. This quickly results in them developing Metabolic Bone Disease (MBD), a serious, debilitating, and eventually fatal disease that turns their bones to rubber...And eventually there is no more Calcium stored in their bones for their bodies to leech away, so any of the bodily processes which require Calcium to happen cease to happen...And in pretty much all living creatures, Calcium is required to perform the bulk of ALL bodily functions, such as nerve impulses, muscle contractions, etc. This means that eventually Metabolic Bone Disease causes paralysis, an inability to breathe, and an inability for the heart to beat. So in-general, these creatures, such as the Bearded Dragon, require at least 2-3 hours under direct, natural sunlight each day or 11-12 hours under an adequate, unobstructed UVB light each day, simply for their bodies to function correctly and ultimately for them to survive...
***Now onto birds...and humans for that matter. Birds, humans, and in-fact most mammals, primates, marsupials, and rodents do not require anywhere near the amount of Vitamin D3 to absorb adequate amounts of Calcium (and Phosphorous for that matter) for their bodies to perform all of the daily, necessary bodily functions. The fact of the matter is that most living creatures, including birds, rodents, and primates, get all of the Vitamin D3 that they need in their daily diets. Imagine for a second if we as human beings would require to be out in direct sunlight for at least 2-3 hours per day, every single day of our lives, just for our bodies to perform all of the intricate processes that our cells require Calcium to perform...That would be a problem...same thing for our dogs, cats, and yes, our pet birds.
TO BE CONTINUED BELOW...