A new bird

I have spoken about Albino and Leucism. And that is the problem of Maslow's Hammer. Everything looks like a nail when you have a hammer. 

So when I saw this bird, I assumed it was a white pigeon. With a genetic disorder. 

Pied Imperial Pigeon

So now I am stuck with how to class this bird. Is it an escapee? 

The bird below is in an Aviary a stone throw away. On one hand, you could say it is a prison although the birds in the aviary all looked pretty well-fed with the open buffet.  

Or a visitor? Prison visitation or checking out the facilities in the aviary? Both birds did not try trading places. 

Milky Stork

To be fair, the Pied Imperial Pigeons were building nests around the exhibits of the flightless birds.