I have been ways worried my poor featherbabies are never getting enough real unfiltered sunlight.
I have also read so much conflicting info about the dangers of using aftificial light, so imo i try to to stick to what is natural.
I also live in an apartment, and it can be difficult to find the perfect time of day, or best window to give your bird the best source of natural sunshine.
But with time, I am sure you and your bird can figure it out.
For example, the last 5 years, i have been dragging my huge bird cages all over my apartment, so they have access to a fully open window and the sunshine.
I also started trying to teach my birds to accept being in smaller "temporary Cages" that I could then place easily on my balcony in the morning sunshine, for example. While watching over them.
After awhile when i would say "lets go get some sunshine" they would be happy to hop into their small cages to enjoy some much needed sunshine and fresh veggies.
It can be alot more work, but they get what they need and learn to work with you happily when they realize how much they can also enjoy and benefit from it.
Actually, I am so proud of my Kiwi (not a parrot) has finally after 5 years of rejecting direct sunlight, now accepts it.
He always got into his small sun cage without trouble and enjoyed being in the sun, while in his cage, but trying to stand with him on my shoudler in front of a window and in direct sunlight would send him flying away almost instantly. As soon as the warm sun would touch him, or I would get too close to an open window, he was gone.
As of last week, and after 5 years of workinf with him, I am a proud mamabird to say, he is no longer afraid.
He has FINALLY embraced the window ledege with thw window wide open in the sun and happily sings away to all the birds he sees. I feel as proud as any mommabird could feel about this.
He still needs to learn and understand that when he gets overheated, its time for a break but together we are working on this. I always keep an eye on him. One small but amazing step at a time.
Is it possible you can put your bird into a window, with the glass wide open..? Or Into a safe and secure cage, while sitting together in the sun on a balcony?
While it may not solve winter sunshine issues, there is plenty of healthy and natural sunshine from spring to fall.
Goes without saying, but always sit with your birds and make sure they do not overheat and are not exposed to potential predators. EVen on a balcony.