Birds rely heavily on insects for food in the spring and summer. In the spring, birds molt and grow new courtship feathers, they find mates, breed and build nests, and females produce eggs. Finally, parents must feed hungry nestlings. Nestlings grow at a tremendous rate while also developing a complete set of new feathers. They have a prodigious appetite. To deal with these demands, birds need plenty of protein-rich, high-fat food. Even birds that eat berries, seeds or greens other times of the year supplement their own diets and feed their young with large numbers of insects in the spring and summer.
This means a healthy population of insects is critically important to the web of life. So, what are the insects eating? Most eat plants. Of the plant-eating insects, 90% are considered specialists, in that they have specific host plants. The leaves of these plants contain chemical compounds that match the nutritional needs of the insect. Over thousands of years, insects have developed tools that allow them to find their host plants at the time in their life cycle when the part of the plant they need is produced.
For insect populations to stay healthy, these links must continue. Monarch butterflies depend on plants in the milkweed family to feed their larvae. Monarch populations have plummeted in recent years as milkweed patches along their migratory corridors have disappeared due to loss of habitat and climate change.
Insect populations are also at risk because of pesticide use, invasive species and the human inclination to favor exotic plants over native species. An ornamental plant may add a splash of color to a backyard, and birds may perch among its branches, but exotics are useless to native insects and damaging to the food chain.
There are many attractive plants that have evolved with our desert environment. They require less water and less fertilization than exotics. They provide nutrition for insects, birds and other animals. Native trees and shrubs offer secure nesting sites for birds and shelter for small mammals and lizards. Using multiple species of natives in your yard fosters a resilient community. Each one of us can repair biodiversity by using native plants in our back yards, front yards, gardens and patios.
Bringing Nature Home by Douglas W. Tallamy
The Forgotten Pollinators by Stephen L. Buchmann and Gary Paul Nabhan
50 Common Insects of the Southwest by Carl Olson