Morning all. My CAG's cage will be in our family room, which is about 14 x 20. It has 4 huge floor to ceiling windows, and 2 skylights. That part of the house is a south facing room. My question is, will he still need a full spectrum light as this room is really bright during the day.
Thanks all!

I believe that windows nowadays filter out the beneficial UV light. For your bird to actually benefit from the sun, he would have to be put outside, or sat next to an open window. For me, having a f.s. light fixture is much easier!

hatWhat I recently "heard" (which means this may not be fact), that if your house was built prior to 1939, the glass is the type that does not filter the beneficial UV rays. If it was built after that, the panes of glass will filter it. Gotta love the old houses!

Not a silly question at all. Wish I had a definitive answer! I do know that all glass filters light in some way and to some extent, whether the glass is U/V coated or not. Also, I have read that an important consideration with window filtered sunlight is the distance the sunlight has to travel from the glass to the object (bird). The greater the distance, the greater the degradation of the sunlight spectrum. This rule applies to F/S lighting as well, and that's why a distance of 14 to 16 inches from lamp to bird is usually recommended.

To find out what this means to you and your application would require some study. First finding out if the windows and skylights are U/V coated (and being large floor to ceiling units and skylights I rather suspect they are modern enough so that they very well might be coated) and second, looking at how far away from the windows the birds are. Remember, having the cages too close to a south facing window in the summer sun could result in good light but a dead bird because of the heat!!

I would expect that F/S lighting will be a much smaller issue for you than it is for me, where I have a room that receives almost no direct sunlight through most of the year. Or, for instance, a breeder that has their setup in the basement. That's not to say that there wouldn't still be some benefit for your birds as well, but at least they already experience a good circadian cycle (night, dawn, day, dusk, night).

Thanks for clarifying what I had heard, Nate.