Creatures Getting Ready for Winter Need Those Fallen Leaves!

Hermit thrush. Photo by © Maria de Bruyn.


By Maria de Bruyn

Autumn is now in full swing with colorful leaves turning brown and falling from the trees that they helped nurture. The berry-producing trees and shrubs, like dogwoods and winterberry, are becoming increasingly bare as the local and newly arriving migrant birds raid their branches.  For a while, the oak, walnut, pecan and hazelnut trees will still have nuts to feed the hungry birds, squirrels and chipmunks, all of whom prepare caches of nuts and seeds to consume during the cold months.

The fallen leaves still have an important purpose as they hit the ground—they provide a habitat for insects and bugs, animals that are important for plants and other creatures.

Top left: Hummingbird clearwing moth. Top right: Eastern tiger swallowtail butterfly. Bottom: Marbled salamander. All photos: © Maria de Bruyn.

Fireflies, moths, butterflies and other insects use the leaf litter to survive the winter. Some overwinter in their pupal state, like the hummingbird clearwing moth and the Eastern tiger swallowtail butterfly. Other butterflies overwinter as adults and then emerge to pollinate our spring and summer flowers and other plants.

Up to 30% of our native bees build nests in narrow tunnels in hollow stems, brush piles and dead wood, while bumble bees hibernate a couple inches underground during the winter, welcoming extra layers of leaves above to protect against the cold.

As leaves slowly decompose, they provide shelter for creatures such as amphibians and reptiles. For example, the marbled salamanders spend their winter days under logs and in leaf litter. Although they largely stay dormant in the cold, they continue eating worms, spiders, slugs, snails, centipedes and many insects.

Top left: Ruby-crowned kinglet. Top right: Hermit thrush. Bottom: Northern mockingbird. All photos © Maria de Bruyn.

Birds consume large amounts of insects in late summer and early fall and then again in the spring, when caterpillars form a large part of their babies’ diets. If we want to promote conservation of the natural environment, it’s important that we “Leave the Leaves,” as an increasing number of environmental and municipal agencies advise.

Some people don’t like the look of leaf-covered yards and fear leaf layers will ruin their lawns. The U.S. Department of Agriculture points out that as leaves disintegrate, they can enrich the soil and lessen the need for fertilizer. Some people mow over leaves, but this will kill many of the adult and pupal insects that are overwintering among them. To avoid too thick a leaf layer over areas where you want grass, you can rake them into piles around trees, onto garden areas and into mulch piles.

Doing this will also help reduce solid waste collection and storage, which is paid for by our tax dollars. In 2015, it was reported that yard debris and leaves accounted for more than 13% of solid waste in the United States. This compacted organic matter can release methane into the atmosphere. Gas- and diesel-powered leaf blowers and trucks used to collect leaves also generate additional carbon dioxide. Use of more electric tools and vehicles would help this situation, but our yards, parks, natural areas and fellow living beings will benefit more if we let the leaves fall where they may.

Happy Thanksgiving!

Maria de Bruyn participates in several nature-oriented citizen science projects, volunteers at Mason Farm Biological Reserve and the Orange County Senior Center, coordinates a nature-themed book club, posts on Instagram ( and writes a blog focusing on wildlife at

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1 Comment on "Creatures Getting Ready for Winter Need Those Fallen Leaves!"

  1. So important! We did this last year and saw more birds and pollinators in our yard this spring and summer.

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