This is a very informative article!

The Optimal Environment: Part Three - The Creative Cage
By Pamela Clark

LINK: The Creative Cage

This article covers topics;

Restoring the Freedoms of Movement and Choice
The Primary Cage Environment
Play-top Versus Dome-top
Sizes and Shapes
Parrots Move Laterally
A Space among the Flock
Visibility Creates Vulnerability
Enhance That Cage
Alternate Perching Sites
The Outdoor Aviary… An Opportunity for Exuberance
Have a Bath?
Wire Issues
Outdoor Diversions
A Need to Go Places….

I thought overall the article was great. I wonder where this woman suggests putting full spectrum lighting (or where she puts her's) when she's promoting play top cages. I think a lot of people don't take that into consideration. Perhaps her birds get enough time outside for benefits, but I think it's something that needs mentioning when writing an article like this to the general public. I don't think a play top cage is at all necessary for a flighted bird. They don't need a mediocre play place they can climb to when they can fly where ever they want to go. For those birds especially I think lighting is more important than a cage play top.