Due to clever design, the top part of the Darryl/Stanley mansion is removable, leaving the bottom part, with the TV, in position, and the top part--the cage--separate for transporting.
When removed, the top part is fitted with wheels so the light but bulky house can be easily moved into a van for transport to an alternate friendly residence when the Birds' ghost writer is travelling.
The wheels are simply inserted into the pipes at the bottom of the cage portion and kept from falling out by that screw which you can see, which is removed and re-inserted--through the pipe--when the wheel is in place.
The complete mansion assembly has wheels, too, to facilitate cleaning the piles of seed husks and nesting material--and the odd feather--which they throw out of their cage and onto the floor of the living room.