Broken bird feeder (Rockville)

This thing has a spring-loaded mechanism that lets the inner core move inside the outer shell, and this part all seems to be intact. I am not sure exactly how it's supposed to work. However, there's a bottom piece that is supposed to fit on to the main structure, but it's so rusted that it doesn't stay connected anymore, so it seems like there's no way to keep bird seed in the feeder. If anyone wants to tinker with it or has another use for it ...