Blackbird flew against a window, had spasms at first, sought shelter under a tarp, and I don't know whether the blood on the beak necessarily means it's a cerebral hemorrhage or whether it could have come from a less critical source. (Maybe the shock from the beak impact rupturing some capillaries?) Also worried a swelling could put too much pressure on the brain, if it's that serious. Currently it's wobbly and sleepy and it's 15-17°C (59-63°F) outside and weather report says down to 9°C (48°F) in the night. A while ago it made attempts to clean its feathers, but always 'reset' pretty quickly. Later it held its head down to the side, so obviously it's an at least medium concussion. For now I'm just allowing it rest and quiet and put some water nearby. Seems to be a relatively young bird, judging by the bright yellow around the mouth. The window has reflective finish but bird of prey stickers on it, but the bird approached the window in an unfortunate angle. (I hope it wasn't distracted or in a hurry because of offspring.) Ever since the stickers such a thing rarely happens at all anymore, only very rarely I see a huge dirt imprint from a particularly stupid pigeon on it. UPDATE: I added a little more shade since it seems sensitive to light, and also to make it less visible, feel more sheltered. It seems to have cleaned its beak a little since last time I checked, as far as I can see. But still breathing heavily. I'm just worried that long-term it might get hungry without the ability to get food, although food might not stay in. I think I'll wait until the evening and then see how it's doing and whether it might need a little snack. But I gotta figure out something to protect it from cats and such.