Do you know what happens when a bird 'runs into' a window that was open? You have to spend the next half hour chasing it around your house with a broom. I'm speaking from experience here.

It's not so bad. I lived in a south east Asian nation for a few years with no glass windows (but large shutters). We would get a bird once week or so. Trick is to leave the window open and close off other exits.

However, with frosted glass and screens you would keep birds out.

When a dove came into my classroom in high school it started to fly in circles and perched at the projector in the ceiling.

Apparently it got confused by the artificial lightning (6500k fluorescent tubes) because once we killed the lights it went straight to the closed windows instead of the open door at the opposite side. We had to draw the curtains of every window except one for the dove to get out :(