Obtain a small amount of small grid hardware cloth. Can be purchased by the yard from most hardware stores. I had some in the basement. Squares are about 3/8" square. Then cut a rectangular section about 1" wider on either side and long enough so that one uncut length will wrap around the lower section of the original suet feeder like a "U". Bend the edges to match the shape of the suet feeder. Then cut at the lower corners of the "U" on the 1" extensions on each side - 4 cuts. This will leave three sections of hardware cloth on each side ready to bend. Bend up the small square of it on the bottom, then double over either side and secure the final side with a twist tie. I used an old bread twisty. Repeat with the other side. It's sort of like wrapping a package.
Step 2: Final Photo
Here's what it looks like all folded up.
Step 3: And now my cat watches birds, not squirrels