What about sunlight?

[taylorc29]

Penny has been acting strange lately, and just now I'm wondering if it has anything to do with the dark curtains I put up in attempt to keep my room cooler during the day.

Could less sunlight cause a bird to become depressed?

[Kumiko]

Have you ever heard of spectrum lighting? It's nice to take your bird out once in a while in the sun.

Tropical birds need 12hours of light and 12hours of night--parrotlets need 10-12hours of sleep, preferably 12 though. Birds will become grumpy, irritable, and probably in your case, depressed.

Spectrum lighting is the closest thing you will get to the natural sun in the house, but some of them... well... suck.

Provide a cage for outside because birds would love to sunbath in the "real" sun (a ting cage will do). Even 10-20 minutes will do. Sun provides the Vitamin D3... birds store that in their liver, so it doesnt need to be everyday. :) Have part of the cage covered so your birdie can escape the sun when it wants to. ;)
Really big heat is during the say so... evenings and afternoons are best since they are the coolest parts of the day.

[Mustang99]

I agree with Rebecca - she's right on. the spectrum lighting is quite beneficial particularly during winter months and gray days. Getting them outside in the sun in a cage is great since even having the cage at a window, they don't get the benefit of the exposure through the window other than enjoying the light. I definitely see a huge difference in our birds and you can tell if they have a couple gray days and I don't use the lighting.