The cafe next to Sheep's Meadow has tables for self-service as well as service. And starlings. After the parents abandon the young they form kindergartens and explore on their own. Not too brainy. The tables are nice spots for sunning, but slippery which makes getting back up difficult.
The air vents usually have bugs in them.
As for being aware of humans, forget it.
I wish I had human subjects who would pose so willingly.