So I was looking on ebay for seed catchers and the cheapest one I found inc shipping was $18.30. Really overpriced, so I made my own. I dug up some old fabric my mother gave me a while back.
: In the method you'll notice I did not measure anything, I just used the ruler for straight lines lol, I'm lazy
What you will need
-Elastic (can get this from an old sheet like I did)
1. Choose your fabric!
2. Holding the fabric over the cage, roughly estimate how much fabric you should cut off, and do it.
3. Hold your elastic over your fabric to estimate how much space you need for it.
4. Use safety pics to keep your rough estimate and to secure your fabric which'll make sewing easier. Note: this wasn't enough space for the elastic, I began sewing and had to restart it all.
5. Make sure you leave a gap at the beginning of each end of the fabric so you can actually pull your elastic through. Sew each side and move the safety pins as you go along to make it easy.
6. Get a bigger safety pin and place it through the elastic. Start feeding the safety pin through the gap you made and pull the fabric back as you go. Do it all the way through.
7. Go back to the gaps you used to feed the elastic through, and sew them up.
8. You're done! Put it on the cage and feel all awesome as you admire your work. Here is how mine turned out, It's a little uneven because I never bothered to measure anything, but it does the job
You should post pics on how yours turned out here!