A glance out at my backyard shows that birds have added some of their favorite plants to the landscape. I’ve never, ever, planted an elderberry, yet each corner of the yard is anchored by these handsome shrubs bearing large clusters of berries every summer.
Pagoda dogwoods are beautifully shaped small trees, and the single one I planted years ago has gone forth and multiplied many times over, providing spring flowers for bees and summer berries for birds (and squirrels).
A neighbor’s backyard mulberry produces seedlings around the yard each summer. This tree is a feeding magnet for many kinds of wildlife when the berries ripen in summer, but it’s on the large side (and not native), so seedlings get yanked.
There’s no canny landscaping plan at work here — the plants appear where birds perched to eat berries and then pooped the seeds — still, I appreciate their efforts. And now it’s time to return the favor.
While adult birds consume seeds and/or fruit the rest of the year, spring and summer bring a major dietary shift. It’s a fact that 96 percent of songbird species feed their offspring exclusively on insects (among the few that don’t are goldfinches and house finches). This high-protein insect diet helps young birds mature quickly, in around 10 to 14 days, and leave the nest before predators become aware of them.
The birds that usually appear at feeders are now busily searching both sides of leaves, twigs, bark and branches and on the ground for arthropods (insects, bugs, spiders and worms). A friend calls this “bird baby food.” Yet for so long we’ve been focused on having perfect plants, choosing those that are advertised as “pest proof” and we’re quick to reach for chemicals if we notice insect damage.
We might as well be saying, “birds aren’t welcome here,” because insects are what parent birds need. Tiny chickadees feed nestlings up to four times an hour for up to 15 hours a day. That means stuffing 5,000 or more insects down tiny gullets before their offspring are able to feed themselves.
Or consider a harried cardinal pair: They follow a feeding schedule similar to the chickadees’, but they raise two broods a summer and feed their offspring for up to a month after they leave the nest, as well. This may require 8,000 to 10,000 insects per brood.
Insects are picky
While it would seem that there are plenty of insects in the natural world, many are things like aphids, that few birds eat. Parent birds search primarily for juicy, plump caterpillars to deliver a high-protein punch.
But most caterpillars come from picky families, their mother depositing her eggs on just one or just a few kinds of plants. This is because plants produce defenses against chewing insects, and caterpillars have had to specialize for eons to overcome a plant’s toxins. Something like 90 percent of caterpillars eat only particular native plants or groups of plants. (Think of the monarch butterfly caterpillar and its complete reliance on milkweed.)
Non-native species of plants and trees simply aren’t recognized as food by native insects (this is why they’re “bug proof”), so they offer little to birds, except convenient places to perch.
Bottom line? Let’s plant more native trees — oak, maple, hackberry and/or dogwood — and native shrubs — chokecherry, wild plum and/or serviceberry. And augment garden beds with native plants like milkweed, virgin’s bower vine, wild columbine, phlox and coneflower.
In this way we can help ease the hectic lives of parent birds in the spring and summer, and ensure that their offspring are robust and ready for life’s challenges (more feedings mean healthier fledglings).
St. Paul resident Val Cunningham can be reached at firstname.lastname@example.org.
Online resources for gardeners
University of Minnesota: extension.umn.edu/garden/yard-garden/landscaping/native-plants-for-sustainable-landscapes/
St. Paul Audubon Society: saintpaulaudubon.org/go-native-sustain-songbirds-wildlife-garden
Native plant website: prepared by Beth Brombach, a native plant gardener: mnnativeintelligence.com
Xerces Society: xerces.org/tag/conservation-comes-home