Fall weather usually means deciduous trees shedding leaves. It's a chore to rake them up, but it's a chore you may want to avoid doing altogether. The National Wildlife Federation says many butterfly and moth species (along with a host of other beneficial insects) hibernate as pupae in leaf piles. If these leaf piles are raked up and taken away, it also means you're ridding your yard of butterflies come spring. And just like in the circle of life, many birds depend on insects in leaf piles to feed their babies. If you can, leave the leaf piles to give Mother Nature a helping hand.