This morning I took a closer look at the area surrounding the bridge. From a distance of course. It seems there are even more toxic warning signs than I saw yesterday, especially in the vicinity of the bridge proper.
I was at the point of departing, when a figure appeared from somewhere under the bridge. It was a human, and put up another toxic warning sign. I waved to him (for indeed it was a man), but he first pretended not to see me, then frantically sought to wave me away.
I decided that the warning signs were bogus and he later admitted it when I went down there after him. He’s got pigeons, but won’t discuss anything until tomorrow.