I found two, TWO! dead hummingbirds outside my glass patio door last week. A male and female. Lying within 6" of each other. I nearly cried. We only have one little male hummer coming to our feeders now.
A few years ago, a Baltimore Oriole left our kitchen window a bloody mess, from attacking it so vigorously. They are fierce! (and loud)
Oh, and the mess on the car? Maybe the cardinal is agitated by his reflection in the side mirror. We have had that happen here.
Don't let anyone try to convince you that nature is kind and gentle. It's a jungle out there!