Every day at around this time, the tree in the courtyard hosts a convocation of black birds. They fill the winter-empty branches with their nearly weightless, dark bodies and the air with their raucous conversation. It's the bird equivalent of a trendy night spot out there, although apparently anyone with wings can get in.
When someone walks through the courtyard, the birds fall silent, as if they had been plotting that person's demise and didn't want to be overheard and caught.
As darkness falls, there's a whoosh as they all fly off together, calling out one last threat. Or promise.