The way you are doing it is perfect, Gail. Birds are all photoperiodic so keeping them at a solar schedule is the only way you can keep their endocrine system working as it should and in tune with the seasons. The exposure to dawn and dusk light (which has a different spectrum than the middle of the day light) is what sets their internal clock (it's like a stopwatch, it's turned on by the dawn light and turned off by the dusk light and the number of hours in between is what tells their bodies which season it is) so it's important that this is done without interference from artificial lights.
Captive parrots kept at a solar schedule have a full molt once a year (after breeding season ends which usually happens in the summer but this depends on whether the bird is a long or a short day breeder). In this molt, they change half their plumage (with the other half the next year). But they often have what is called a partial molt around mid-January. This is because this date is around 20 days after the winter solstice (around Dec 21) when the days begin to get longer and, in 20 days, the daylight period is 20 minutes longer which is the difference between the seasons in the tropics and which studies have shown birds can register.




