Oh my goodness....irresponsible bird owners make me so upset. I can see having an aviary with a few tropicals in it but to put exotic pet birds in a working greenhouse is just not a good idea. They are not easily trained to stay on their cages unless you clip their wings. if you have them in a greenhouse, you clip their wings so they can only go down if they decide to fly, and a partial clip can be even better for a place like that so they could fly just so far. I would be more afraid of them killing themselves trying to fly out and hitting the glass walls. Some kill themselves flying into walls and windows in a normal home setting if you are not careful. I bred exotic birds for years and I would never think of putting them in the greenhouse (but this one was attached to the house, so that is a bit different). I can imagine what they were trying to do but it obviously did not work. Too bad for both birds and humans.
I can not help but wonder what people are thinking when they do some things.
