I adopted my amazing Umbrella Cockatoo from Northcoast Bird Adoption and Rehabilitation Center in 2000.  I named him Pele (pronounced PAY-LAY) after the Hawaiian deity of fire, lightning, dance, violence, and volcanoes.  All of which fit his explosive personality to a tee!  He is a large wild caught male breeder who loves to display ostentatiously and stamp his feet.  He was imported through California in 1980 as an adult so his age is unknown.  He is aggressive and dangerous to other birds which promptly ended his breeding career.  He is unfriendly towards strangers but very affectionate towards me as we have a strong foundation built from a long history of trusting and loving interactions.  He is up for cuddle sessions, but is not a velcro bird - something I continue to strongly cultivate and encourage.  He is very energetic and loves to chew, hop, dig in the dirt and flap his wings.  He is extremely vocal but does not scream for attention nor does he talk.  Pele is the reason for the Natural Inspiration's cage size, dimension orientation, and design features. 
     When I first brought him home I put him in his "big" new cage, a 3x3.  He was a very unhappy bird on many different levels.  I soon upgraded him to a 3x4 dome top cage.  This gave him a bit more room, but after I added his toys and perches he was unable to flap his wings nor could he hop - something he loves to do.  I then built him a 6x6x6 custom cage.  This gave me the opportunity to add lots more enrichment items and gave him enough room to flap his big beautiful wings and get out lots of that umbrella energy.  I noticed this cage, not having grates on the bottom allowed him to hop, roll over, and burrow on the floor of his cage.  During my stay in Australia I watched time and time again the exuberant play of cockatoos on the ground.  This is why there are no grates on our bird cages, among other reasons relating to time and cleanliness. 
     Pele was a much happier bird, but still I could feel there was more that needed to be done.  He loved being on the "floor" of his cage, but he didn't like the fact that it was on the floor!  I also noticed the cage was not really long enough to allow his wild displaying (if you have an Umbrella or Moluccan you know what I'm talking about - the winding, twisting, head banging hops!)  So I tore his cage apart again and he moved into a 4x4x9 foot long cage.  This cage he absolutely loved!  It had all the features cockatoos enjoy and enough space, in the ideal dimension (length) to enjoy it.  He has lived in this cage for the past 6 years and it has worked very well.  It houses all the cockatoo "essentials" that I believe are nothing short of mandatory for keeping a sensitive and intelligent creature contained...foraging tray, bathing dish, boing, rope swing, 2x4 perch, piñata, cardboard box, bell, and a few rotated misc toys.  I truly consider this to be a bare-minimum "starter set" for all species of cockatoo.  In order to fit all of these things into his cage AND still have enough room for him to fully flap his wings and play/hop on the bottom - it HAD to be that size.  It was, however, just a tiny bit cramped so I built him a 4x4x12 cage recently.  This size cage I am completely satisfied with as providing ample room for parrot movement and stimulation while being realistic for indoor housing.  If you are thinking of purchasing (or already own) a cockatoo, please read some of the articles discussing cage size for additional information.  Also check out www.mytoos.com for another viewpoint of cockatoo ownership.  He also enjoys his outdoor aviary during the warmer months of the year.