March: Spicebush Swallowtails

The first-graders stare upward, eyes big, foreheads furrowed with disbelief.

Above them, a lime-green caterpillar grasps a twig with rosy feet. Sky-blue spots adorn its sides, and its yellow eyes sport huge, dark pupils. It looks like it’s crawled out of a TV cartoon or flown in from some far-off planet.

It’s a Spicebush Swallowtail – one of the most engaging caterpillars in our gardens. Our first grade classes focus on the many ways that caterpillars hide from or fool predators. Spicebush Swallowtails have some of the best tricks.

Soon after our spicebushes leaf out in the spring, small folds start to appear in some of the leaf tips. Open one gently, and if you’re lucky you’ll find the tiny caterpillar that chewed a crescent in the leaf, then used silk to pull the resulting flap over itself.

Like most Swallowtails, young Spicebush caterpillars wear what we call “bird poop” colors. The blend of brown and white makes them look more like unappetizing droppings than tasty caterpillars.

As they grow older, however, they discard that look for the color and markings of a small snake. Those gorgeous yellow eyes? They’re fake. The caterpillars tuck their real heads, with their real eyes, beneath the bright green disguise.

Then, just before they make their chrysalises, they turn orange or gold.

They hibernate in their chrysalises through the winter. A number of Shamrock classrooms have Spicebush Swallowtail chrysalises right now, waiting.

As the days grow warmer, velvety black butterflies will emerge, with a shimmer of blue-green. We’ll start to look again for folded leaves.

Eastern Tiger Swallowtails

Early spring is also a good time to start looking for Eastern Tiger Swallowtails. These big, bright yellow butterflies are easy to spot and identify.

It can be tough to locate Tiger Swallowtail caterpillars. Tigers lay their eggs on the leaves of tulip poplars, usually far out of reach. But a handful of poplar saplings have sprung up in our garden beds, and sometimes we’ll find a caterpillar or two on them.

Tiger caterpillars also start out with the bird-poop look, and put on brighter colors as they get older.

Their fake eyes aren’t nearly as spectacular as those of their Spicebush cousins. But when disturbed, they shoot out an impressive set of long, orange horns.

Tiger Swallowtails get their name from the tiger-like stripes on their wings. A bit of history: a North Carolina Tiger Swallowtail was the first North American butterfly to be drawn by a European. Artist and explorer John White was part of the first English efforts to settle in the New World. In 1585 and 1586 he made dozens of drawings of the people, plants and creatures he encountered, including this Tiger.

A Year in Shamrock’s Gardens, the 2020 calendar produced by the Shamrock Gardens PTA, celebrates 10 years of our school’s butterfly gardens. Thanks to Lexie Longstreet for the generous donation that allowed us to give a calendar to every family and staff member at the school.