You're the signature guy
Don't have a picture but here in Brooklyn I see every late afternoon in the summer, like 7/8 o'clock, small flocks of smallish black birds flying swiftly around and not fluttering their wings much. I call them stunt birds because it looks like they do stunt flight maneuvers. I never see them too closely since they fly higher up and are just pitch black with no pattern. Any idea what bird these could be?
Bats? They fly erratic routes, not straight, darting here and there.
Swallows
Close! Only thing is that swallows have pale bellies while the ones I see are pitch black. By googling swallows I assume they are Chimney Swifts. Can that be?
You can also tell a swift from a swallow by way longer, pointier wings and a "flying cigar" shape. If you have any kind of tail visible you 99% have swallows.
Newborn bunny.
First new mammal in forever.
You can probably attract opossums if that interests you. I believe those are actually marsupials, and you can add a new category. (You may never get rid of them once they come.)