As a backyard bird enthusiast, I find watching the bluebird’s life cycle unfold in my yard to be fascinating. Each year, I anxiously await bluebird nesting season and feel a sense of accomplishment when another brood has fledged, even though my role in their life was minimal. I simply provided a nest box while the parents constructed the nest, incubated the eggs, and tended to the young.
Backyard birdwatchers know just what seed or suet to put out to entice certain birds to their yards, but insects are also an important food source. You may be surprised to learn that ninety-six percent of all terrestrial bird species rear their young on insects. Flies, beetles, and crickets may be on the menu but caterpillars are particularly important. This means if you hope to have bird reproduction occurring in your backyard, your yard needs to sustain a healthy insect population. When I say healthy, I mean large numbers, considering more than 5,000 caterpillars are needed for just a single clutch of chickadees (which incidentally, might also find a bluebird nest box to be desirable real estate).
So how do you go about supporting insects, especially caterpillars in your yard? The answer is native plants. Your landscape doesn’t need to be 100% native, so there’s still room for turfgrass for your kids to play or a special hand-me-down plant that holds sentimental value. You want to strive for 70% native. Research on Carolina chickadees found that populations could only be sustained when non-native plants represented 30% or less of the landscape’s vegetation.
Why are natives so important? It’s all about relationships. Many plant-eating insects can only eat species with which they have co-evolved, hence native plants for native insects. Plants have defenses, and native insects are not often equipped for dealing with the defenses of non-native plants.
You might also need to change your philosophy to be more tolerant of insect “damage”. Let’s think about the monarch caterpillar, which feeds exclusively on milkweed. While it might seem alarming to have your garden milkweed reduced to nubs, great things are happening. Your yard is supporting a native plant which is supporting a native insect, which is supporting native birds.
Plant selection can be a daunting task, but Clemson Extension has resources to help. HGIC 1852 An Introduction to Native Plants for South Carolina Landscapes provides some basic information along with the website for Clemson’s Carolina Yards Program. Within the Carolina Yards website, you’ll find a plant database that can help you make more informed decisions when it comes to adding plants to your landscape.