The cages in corners do not get enough natural light in the room where my birds live. I have LED bulbs in the ceiling fan lights and a floor lamp with three lights than can be independently aimed in different directions, there are LED lights in those as well. The LED means that I do not have to worry about energy costs.
One cage is still not getting adequate light (the behavior of budgies can be positively influenced by quality adequate lighting). I'm thinking of some kind of top-of-the-cage light, do any of you have that?
The reptile section of pet stores usually sell heat lamps that are meant to heat up reptiles. maybe you can buy one of those and find a way to put it above their cage? Obviously don't get a heat bulb, just put a normal full spectrum bulb in the lamp instead.