I love bluebirds - we have them at our farm. One year, a momma bird built a nest in the flue of an old woodstove we had in the old farmhouse and a couple baby birds fell down into the stove. We had to rescue them - they were so tiny and pretty!!
I've had to rescue a lot of "into the window" birds at my place. Most just need a moment of rest and they're on their way.