Need for light
Birds are healthier, look better, and may behave better if they are exposed to natural or full spectrum light (with ultraviolet light - UVB) on a daily basis. Natural sunlight or full spectrum lighting with UVB is necessary for a bird to synthesize vitamin D, which is essential for the proper regulation of calcium and phosphorus levels in the body.
Problems associated with insufficient light:
Some birds, such as African Grey Parrots, are especially prone to low calcium levels (hypocalcemia) if they have insufficient vitamin D as a result of not having adequate exposure to full spectrum lighting.
Inadequate light can lead to behavior problems such as feather picking, biting, and screaming.
Breeding is often linked to the photoperiod (amount of daylight). Birds may not breed if there is inadequate light.
Solutions
Provide a total of 10-12 hours of light
During mild temperatures, take your bird outside in his cage, with the cage doors securely latched. Safety is important, so do not leave your bird outside unattended, and be sure the bird has access to shade. Late morning hours are often the best, when it is not too hot, and insects are not as abundant.
If your bird cannot go outside, provide several hours of full spectrum light with UV-B. Set a light timer to provide the appropriate amount. Place the full spectrum light with UV-B 18 inches above the bird. Regular fluorescent bulbs do not produce the proper spectrum of light, and some believe the magnetic ballasts produce flicker that is very irritating to birds who can easily detect it, when humans cannot. Recommended bulbs include True-light-Solux, Vita-lite (Duro-Test), Activa (Sylvania/Osram), Arcadia Birdlamp, and ESU Avian Birdlamp. Ott bulbs provide full spectrum light, but not UVB.
For breeding birds, gradually increase day length from 10 hours daily to about 16 hours daily.
Need for darkness
Most species of companion birds originate from tropical areas. There, they usually experience 12 hours of daylight and 12 hours of darkness. As a pet, birds require more sleep than we do, and most continue to need at least 10 hours of sleep time daily. Lights and activity will keep a bird awake, since his instincts are to stay awake during this time when predators may be present. He may be able to sleep while there is noise, but movement will keep him on the alert.
Problems associated with insufficient sleep
Insufficient sleep leads to stress, and stress can lead to behavioral problems such as feather picking, biting, and screaming.
Health problems can also result from sleep deprivation, which can lower a bird's immune response to disease.
Insufficient darkness may signal some birds to breed. Cockatiels are one species that is very sensitive to increased photoperiod, and may be prone to chronic egg-laying if exposed to long periods of light.
Solutions:
If the household is quiet with no movement for 10-12 hours, simply cover the cage while the bird sleeps.
In other cases, provide a separate, small sleep cage in a dark, quiet area of the house.
If you rise and leave for work early, keep your bird in a separate darkened room. Set a radio, lights, etc. on a timer to awaken your bird at an appropriate time. (If you and the bird go to bed at 10 pm, set the timers for around 9 am.)
By making some adjustments in schedules, obtaining some additional equipment, and using a little creativity, you and your bird can be "rest assured" that the proper hours of light and dark are provided for optimum health, fitness, and disposition.