THE VALUE OF ULTRAVIOLET LIGHTING
Both birds and diurnal (active during the day) or crepuscular (active at dawn and dusk) reptiles require exposure to ultraviolet light, which in nature comes from the sun. This type of light can prevent various health and behavioural problems.
Although activities such as bringing the bird cage or reptile enclosure outside on a hot day can be fun and enriching, our Canadian climate does not make it feasible to provide direct sunlight every day for the appropriate amount of time required. Placing the cage or enclosure next to a window is not sufficient as glass filters out ultraviolet light. Instead, ultraviolet light must be provided through an ultraviolet bulb.
Understanding Full Spectrum vs Ultraviolet Lighting
Full Spectrum Light – Full-spectrum light is an artificial light that mimics natural light as closely as possible. The sun’s rays are full-spectrum and includes infrared, visible, and ultraviolet light. Not all marketed “full-spectrum” light bulbs that you can buy actually produce beneficial UVA and UVB. Full spectrum light bulbs found in pet stores will provide these essential ultraviolet rays.
Ultraviolet (UV) Light – Ultraviolet light is all around us, although human eyes are unable to detect it. It is a type of electromagnetic radiation that falls between visible light and x-rays, and helps with producing vitamin D. UVA and UVB are the two primary types of UV light that reach the earth’s surface.
BIRDS AND UV LIGHT
A UV bulb is essential to a bird’s health and overall well being. Ultraviolet rays from the sun stimulate hormones that are responsible for the growth of feathers. This helps tremendously when a bird is moulting, a natural occurrence of new feathers replacing old feathers that happens 2-3 times a year. Without this invaluable light source, the uncomfortable moulting process can take much longer, and cause undue stress on the bird.
Birds have tetrachromatic vision (they have a fourth cone in their retinas) which allows them to see ultraviolet light. This allows them to identify friends and foes by illumination of this light on their ultraviolet-reflecting feathers. While the birds’ feathers reflect UV light, most plants absorb it, causing a huge contrast between the bird and the environment around them. Humans have trichromatic vision and cannot see this light.
Benefits of UVB – UVB is necessary for the bird to produce Vitamin D3. Precursors for vitamin D3 are secreted by the preen gland and spreads over the feathers during preening. When the precursors are exposed to UVB, they are converted into active vitamin D3 which is then ingested upon further preening. Without this vitamin the bird is unable to absorb calcium, which can cause a tremendous amount of health problems.
Benefits of UVA – There are many psychological benefits to providing UVA, namely to help reduce or eliminate abnormal behaviour such as feather plucking, nail biting, phobias, aggression, and screaming to name a few.
Without UVA, birds are essentially rendered colourblind as they cannot identify friends and foes through illumination. This can cause the bird to act out aggressively or with fright.
Choosing a Bulb – The best bulb option is one that is designed for birds. A bird-specific UV bulb differs from a reptile-specific UV bulb in that the amount of UVA and UVB output are balanced for birds. These levels are skewed in a reptile-specific bulb to produce more UVB than UVA. Offering a bulb that produces too much UVB can cause eye damage.
Replace the bulb every 12 months. This should be before the light starts to flicker because birds can see this long before humans can. After 12 months the amount of beneficial UV output declines, even if the light is still shining. Write the replacement date on the bulb so you know when it is time to change bulbs.
REPTILES AND UV LIGHT
Not all reptiles require UV light, and those that require UV light do not necessarily need the same levels of UVB and UVA. A desert reptile such as a bearded dragon would receive more direct sunlight, and therefore more UV, than a crested gecko who lives in heavily forested jungles and receives filtered sunlight through the leaves. A Pet Counsellor can assist you in determining which lighting your reptile requires.
Benefits of UVB – Most diurnal and crepuscular reptiles require UVB light in order to manufacture vitamin D3. This vitamin is used to help the reptile process calcium. Without it, calcium passes through the digestive system unused. A calcium deficiency can results in Metabolic Bone Disease (MBD), a disease that most diurnal reptiles are susceptible to if UVB is not provided, and can cause brittle or deformed bones.
Benefits of UVA – UVA light alters a reptile’s vision and perception of their environment. Without UVA, certain reptiles may struggle to find a food source or determine whether something is a potential mate or potential predator. This confusion can affect behaviour, breeding, and result in aggression.
Without UVA reptiles are essentially colourblind, and abnormal behaviours can stem from this.
Choosing a Bulb – Not all reptile UV bulbs are equal. Some produce higher UVB levels than others to replicate the amount of sun exposure that each reptile would find in their natural habitat. Ask a pet counsellor for assistance in choosing the right UVB level for your reptile. Keep in mind that more is not necessarily better. Offering a bulb that produces too much UVB can cause eye damage.
Replace the bulb every 6-8 months. After this time the amount of beneficial UV output declines, even if the light is still shining. Write the replacement date on the bulb so you know when it is time to change bulbs.
PROVIDING UV LIGHT
Choosing a Fixture – There are many fixture options available for birds and reptiles. For birds, the avian floor lamp is most popular because the cord is inaccessible to the bird who may otherwise chew it. The design also makes it easy to position the bulb above the cage. For reptiles, if a tube UV bulb is chosen then a ballast light fixture would be most appropriate. If a compact coil UV bulb is selected, a deep dome reptile light fixture will work well because it can accommodate the coil bulb’s long length.
Avoid light fixtures with built in dimmers as using this feature can drastically reduce the lifespan of the bulb.
Fixture Placement – Proper fixture placement is essential in safely providing UV light. The light should come from above (like the sun) and sit approximately 12-14 inches away from where the bird or reptile will be, and safely out of their reach. Light that comes from the side can cause eye damage. An avian floor lamp or light fixture bracket can help in placing the fixture above the enclosure.
Note that if the enclosure has a glass top/lid, the UV light will be filtered and will be insufficient for the animal.
Creating a Photoperiod – A photoperiod is the duration of light that a living thing is exposed to in a day. Photoperiods help animals dictate certain behaviour such as hunting or foraging, breeding, basking, etc. Timers are a great tool in creating a natural photoperiod because they can turn lights on and off at set intervals to establish a consistent photoperiod. For reptiles, as days get shorter, the photoperiod in captivity can be reduced (8-10 hours). As days get longer, the photoperiod can increase (10-12 hours). For birds, 10-12 hours of darkness ensures proper rest. They should be exposed to 7-9 hours of UV light during the day with a break period at noon, or alternatively provide shade or a snuggle hut so the bird can self-regulate their exposure to UV lighting. Over exposing the bird to UV lighting (ie. leaving the bulb on too long each day) can cause hormonal imbalances such as chronic egg laying or aggression.
Baby and adolescent birds are exposed to less ultraviolet light because they spend the majority of their time in their nest. The amount of exposure to ultraviolet light increases as they mature.
For more information on your pet’s Four Basic Needs, check out some of our other Petland Tip Sheets for birds and reptiles:
- Bearded Dragon
- Hermit Crab