On World Migratory Bird Day, May 11, we celebrate the bird species that travel thousands of miles from their winter homes in the tropics to raise their young in the northern hemisphere, including Vashon.

Every spring, we wait to see the vibrant splash of color that is a western tanager, and the resplendent displays of the rufous hummingbird — to hear the first jubilant song of a black-headed grosbeak, or the haunting melody of a Swainson’s thrush.

You don’t have to know the names of these visitors to experience the thrill and wonder they bring. They are living exclamations of the biological connections of the Americas.

Imagine never seeing or hearing one of these hemispheric messengers again.

Songbird populations in the northern hemisphere have experienced large-scale declines over the last 50 years. Loss or degradation of habitat — places in our landscapes where birds can find the right kinds of food, shelter, and nesting requirements particular to each species — are strongly implicated in these declines.

The special emphasis for World Migratory Bird Day 2024 is insects. Most of us know the importance of insects for pollinating, but insects also play underappreciated roles in our ecosystems as consumers and processors of plant matter into forms other animals, like songbirds, can use. But the populations of some major insect groups have shown troublingly large declines in the last half century.

Why does this matter to birds?

The massive loss of insect populations along migration routes and at breeding sites threatens bird survival and reproduction. Some songbirds, like warblers and flycatchers, don’t eat much of anything else besides insects.

But even songbird species that prefer seeds or fruit need the high-protein resource that insects provide to feed their nestlings during breeding season.

All kinds of insect protein are helpful, but the fat, juicy caterpillars of moth and butterfly larvae provide the biggest protein payoff. And if those protein sources are scarce or absent from the landscape, songbird reproduction will fail. Most songbirds in the wild live less than a handful of years, so failure to successfully reproduce in any one year has dramatic consequences for songbird populations.

There is a connection between insect and bird declines, and there is something we can do about it in our home, farm, and public landscapes.

Research shows many insect species require specific plant species — those they have co-evolved with — to serve as hosts for their eggs and larvae. Native plants are essential for the health of most insect populations. And there is a direct relationship between healthy insect populations and the health and breeding success of songbirds.

Studies show that more than half the area of home and public landscapes across the U.S. are dominated by non-native ornamental plant species. Non-native ornamentals may please our eyes, and some have other positive attributes, but most of them cannot function as host plants for most native insects. Only coevolved native plant species can play this role.

This is why respected organizations such as the Xerces Society for Invertebrate Conservation, the National Audubon Society, the National Wildlife Federation, and others recommend increasing native plant species in our home and public landscapes as much as possible as one of several key strategies for reversing both insect and bird population declines.

Northwest avian biologist John Marzluff and his students at the University of Washington have shown that suburban and rural landscapes, like Vashon’s, can support healthy populations of many species of songbirds if we retain and restore the right habitat features. A big part of this is to reinvigorate our landscapes with a diversity of native plants to serve the diverse insect populations that directly support breeding bird populations.

Migratory birds lead complex lives that require healthy habitats in winter as well as in their summer ranges, along with suitable places to rest and refuel along their migration pathways. It is important to protect and restore all of these places, but building healthy breeding habitats is something we can do right here.

By planting for the future with native plants, we can pass on the wonder of migratory birds to our children and grandchildren.

Jim Evans is an ecologist, educator and member of the Washington Native Plant Society and the Society for Ecological Restoration. He serves on the board of the Vashon Bird Alliance and can be reached at frangula54@gmail.com.