It is very rare, but when it happens it doesn't usually have these results. So after I heard the knock on the window and went downstairs to see, I wasn't prepared to see that it had died. It was darker than the House Sparrows that constantly visit. And smaller too. In fact, the more I thought about it, I couldn't recall ever having been witness to a House Sparrow having an accident such as this.
Swamp Sparrow, juvenile: finely streaked below. Similar to Lincoln's and Song, but wings and tail are more reddish.