You could but I doubt it would be very effective. Seems like it would be too low in the middle and too high on the sides. The idea is the birds can get their backs up against the pad and a sloping surface lets them choose just how close they want to be.
If you don't care about the spare, you could mess around with bending it to see what more useful shape might be possible.
If you don't care about the spare, you could mess around with bending it to see what more useful shape might be possible.