If you have predators where you are the screen door will do nothing to keep them out. Will there be a door on the little hole? And what kind of mesh/wire do you have covering the big hole? Will the birds be roosting as high as the big hole/window? If so that , will you be covering it during bad weather and winter?
I plan to cover that hole as soon as I get the materials, and to dig and put some plywood under the zoom itself. And yes they will be as high as the window, and for netting I'm going to use Avery netting