What does it mean if you find a black bird in your house?

It is considered a bad omen, just like seeing an owl on top of your house. However I work in a building with large gl doors and we always have black birds fly inside the building which we then have to catch and release. Guess what? After having hundreds of black birds over the years fly into the building not one bad thing has ever happened. I would not worry about it even though it seems freaky. But if your really worried about it you can always do what is called a sage cleansing where you burn some sage and let the smoke run through each room of your house. This is said to remove all evil from that area.