Migrants and Residents

Are you eagerly awaiting the arrival of spring butterflies? Wait no longer because most butterflies are already here! The Monarch’s spectacular migration receives so much publicity that most people assume that all butterflies migrate south in the fall. Not true, most butterflies are permanent residents. They and their offspring rarely venture further than 1⁄4 mile from their natal site unless they are swept away by our cruel Midwestern winds or are sad victims of habitat destruction. The exceptions to year-round residency are few: Monarchs, Sulphurs, Painted Ladies and migrate north to lay eggs on members of the pea (clover) family. Red Admirals and Painted Ladies migrate to Arizona and New Mexico in fall. Their offspring head north in spring to nectar on early bloomers and search out Nettles to lay their eggs. We may even see Monarchs in late April, part of the northwardbound wave of generational migrants seeking Milkweed.

Scientists don’t yet know why the U.S. subpopulation of Monarchs migrates north in spring instead of remaining in their tropical home in Mexico. Wouldn’t that be easier? Unlike our native butterflies, they are unable to survive winter in the temperate zone so they must fly south in fall to survive. The southern fall flights are triggered by changing temperatures and length of daylight, not food supply. Monarch Watch assures us that their favorite food, Tropical Milkweed, does not affect the migration’s timing.

Resident Breeding Populations

your garden, you should see them every year. A resident butterfly is far more secure in your sanctuary than one that is looking for a habitat because even short journeys can be hazardous to a small aviator. Urban obstacles to travel include huge buildings, acres of concrete and air pollutants. Rapidly moving vehicles may be their chief predator!

Summary

Most insects hibernate rather than risk thousand-mile journeys to complete their lifecycles. Even resident butterflies are at risk for the perils of travel if they are forced from the security of your garden by too much cleanliness or careless plant decisions. Beware of killing the overwintering stage, eradicating the host plants or removing native and/or heirloom flowers to install sterile hybrid flowers. If your residents are evicted, another gravid female must find your garden to establish her species all over again.

Establishing a Resident Breeding Population

Like Monarchs, Cloudless Sulphurs migrating each spring and fall depend upon nectar-rich flowers. But their caterpillars eat Sennas rather than Milkweeds.

Red Admirals. For the rest, you risk killing next year’s butterflies if you aggressively clean-up your garden. In early spring I hand-crumple and drop in place all debris not already broken down by Mother Nature, including twigs and branches. Nothing leaves my garden. Not only am I preserving my butterflies, native bees and fireflies, I don’t ever have to buy mulch.

Seasonal Butterfly Migration

Clouded Sulphurs, Orange

Sulphurs and Cloudless Sulphurs overwinter along the gulf coast. In spring and summer, their offspring

The definition of a butterfly garden is an area that supports resident breeding populations. That means all resources for the four stages of a butterfly’s life are present. For the eggs and caterpillars, the garden must contain the obligatory host plant for each desired species. Adult butterflies need an abundance of nectar-rich flowers from March to November’s killing frost. Caterpillars and adults require sheltering plants for nighttime repose, chrysalis formation and winter hideouts. Leaving a portion of your yard more natural with “weeds” and a wood pile meets these needs.

It only requires one gravid (“pregnant”) female of a species to establish a resident breeding colony if she finds her host plant in your yard and the subsequent offspring successfully go through their lifecycle to reproduce every year. Depending on the species, any stage may overwinter. Once a species of butterfly has established itself in

LENORA LARSON Butterfly Maven

In 1994 when I began butterfly gardening, I had never heard of a Pipevine Swallowtail, much less seen one. But my new butterfly book said that they lived in Kansas so I planted a Pipevine, Aristolochia macrophylla* and set vigil. Several years later I saw her, black with iridescent turquoise wings, laying eggs on my Pipevine. Voracious herds of gorgeous caterpillars followed and the rest is history. Fast forward 25 years and Pipevine Swallowtails are by far my most numerous butterfly. They have three broods each year so they fly in my garden from April to August and so many caterpillars are on my six Pipevines that I can hear them munching! They survive winter in their chrysalids slung by silk threads on stems and twigs. They are so well camouflaged that I rarely see them, but birds and rodents find them for winter snacks so every chrysalid is precious.

* Pipevines are rarely found at nurseries and plant sales. However, we will have two natives and the South American species at our Paola Plant Sale on April 27, 28, 29, 2023.