In episode "Glittering Jewels", not listed on IMDB, a page from a library book says "Ravens steal anything that glitters and leave a bright object in it's place." The apostrophe is inappropriate. See more
Felix the cat, / The wonderful, wonderful cat. / Whenever he gets in a fix / He reaches into his bag of tricks. / Felix the cat, / The wonderful, wonderful cat. / You'll laugh so much your sides will ache. / Your heart will go pit-a-pat, / Watching Felix the wonderful cat.