I've been trying to figure out how to introduce nesting material to the backyard birds for a while now. I gave the garage o' parts a hard look the other day and picked out this medium sized baking pan as the shell for the box to hang on the fence or tree. With the other parts I added, I can change out the material contents whenever I want to and offer a variety of materials that can be fished out through the metal screen. I'll let you know how it goes when the nest building starts back up again.