HUGE Owl Nest

I'll admit the title might be deceiving, so I'll explain. Where this nest is located is an old grain silo that is owned by Wolf Creek Nuclear Operation Center or WCNOC for short. They modified in 1999 for people to climb to the top for 360 deg observation, by putting in a door way and windows, along with a spiral staircase. They called it Eagle Nest Tower.

Well this year a Barn Owl couple decided to take up residency in this tower. So WCNOC closed it by padlocking the door, and they installed a nest cam. It can be viewed at http://www.pixcontroll​er.com/barnowl/. The owlets are now getting to the age, 40+ days, where they are venturing out of the actual nest area. There is straw with the common crushed up pellets, one area being the nest bowl. They are now at the stage where they can be entertaining.

There's also a live chat associated with it. I posed a question on the live chat since I've observed the 2 oldest owlets finally step off the straw and walk on the flooring out of camera view. Up until today they would not step off the straw area. The question is; Would they be considered to have fledged by doing so?

1. Is the straw area the nest?
2. Keep in mind this is a huge grain silo. It would be more in line to compare it to a barn.
3. Replies I've got so far, keep referring to them having to know how to fly. I don't think that flying is a requirement. What about all the eaglets the slip, fall out of nests that do not know how? Or how about baby birds, such as Robins, that do not know how to fly when they jump from the nest? They are considered to have fledged when they do.
4. If there were other owl nests or just other nests inside this silo, would the owl's nest encompass those too? If not, than the straw area, the area maintained by mom/dad Barn Owl, would be the nest, and going outside or off that area would they have left the nest. It's just easy for them to walk, or hop to and fro.

First image is of the exterior of the silo/barn owl nest. The second is from a screen capture of the nest itself.