Most desert trees are legumes, meaning they produce pods. (Beans and peas are also legumes.) Masses of spring blooms gradually give way to lengthening seed pods that ripen at the height of summer. This is just when most species are scrambling to feed families of babies.
The crunchy fare provides sustenance for desert critters including coyotes, javelinas, Harris’s antelope squirrels, pocket mice, kangaroo rats and rock squirrels. Some of these animals are destined to become prey for meat eaters like owls, hawks, coyotes and desert snakes. Through this dynamic cycle, ironwood, mesquite, and Palo Verde trees set the table for wildlife.
Desert legumes also have an almost magical ability to feed the desert underground. Desert soils are notoriously lacking in nutrients due to aridity and lack of organic matter. Legumes coexist with soil bacteria that provide surplus nitrogen to their root systems. High levels of nitrogen are essential to the development of protein, making the legume pods very high in protein. Nitrogen helps nearby shrubs and annuals grow, which provides more forage for animals like lizards, desert tortoises and cottontail rabbits.
As a bonus, trees also create microclimates of shade where tender sprouts such as saguaro cacti grow. Animals like jackrabbits and javelinas wait out the midday heat under the protective drape of ironwood branches. Crawling on the branches and among the bark, a variety of insect species feed on nectars, saps and the bark itself. As they flourish, these insects become a protein rich and often juicy addition to adult and baby bird diets.