A New Solution
My friend Ruby suggested putting a piece of wood diagonally across the railing of the fire escape and hanging it from there. A perfect solution, I think.
She also offered to make notches on either end so I could secure it to the railing instead of laying it on top.
Here’s the issue. Because there’s no open end on the railing that would allow me to slide the feeder on and off, I bought this hook that I can easily open and close in order to remove and re-hang the feeder. So the wood piece would have to be thin enough to fit that hook, which might make it too thin to cut notches into. It might be easier to just use a more substantial piece of wood that I could just pull aside every morning from the end closest to me in order to remove and fill the feeder?