Tent caterpillars emerge into spring leaves

The air carries the sound of chewing near Pawlet this morning. If you step close to the black cherry trees along the woodland edge, you can hear it clearly: hundreds of tiny mandibles working through fresh leaves. The eastern tent caterpillars have emerged from their winter eggs just as the canopy reaches full leaf-out, their timing matched to the moment when sugar maples and cherries offer the softest, most nutritious foliage of the year.

The white silk tents appear overnight in the crotches of branches, each one housing a colony of caterpillars that hatched from the same egg mass. These are not random gatherings but siblings that will spend their larval lives together, leaving the tent each morning to feed and returning each evening to the safety of their communal shelter. The tent itself serves as more than protection. Its silk walls trap heat from the sun, warming the caterpillars inside and allowing them to become active earlier in cool spring mornings than they could manage alone. When the colony feeds, they move as a group along silk trails they lay down, following pheromone markers that lead them to the best leaves and back home again.

This synchronized emergence creates a brief abundance that ripples through the ecosystem. Red-tailed hawks hunt more frequently near infested trees, not for the caterpillars themselves but for the American robins and other songbirds that feast on them. The robins arrive in waves, sometimes dozens of them working a single cherry tree, plucking caterpillars from leaves and tent walls. Ground beetles patrol beneath the trees, capturing caterpillars that fall or descend to pupate. Even the ants benefit, finding protein-rich frass beneath the feeding colonies and sometimes raiding the tents themselves for smaller caterpillars.

The trees endure this annual defoliation with surprising resilience. Black cherry and sugar maple have evolved alongside these caterpillars for thousands of years, and both species can refoliate after losing their first flush of leaves. The timing works in the trees' favor too. By late spring, their root systems hold enough stored energy to push out new leaves, and the caterpillars will have pupated and dispersed before the second set of foliage fully develops. The defoliation may even benefit the forest floor plants, allowing more light to reach the mayapples and ferns below during their critical spring growth period.

Step closer to one of those cherry trees now. The sound of feeding intensifies as the morning warms, and if you look carefully at the branch tips, you can see the fresh damage where yesterday's solid green has become lace. The caterpillars themselves are easy to spot: blue-black with white stripes and a row of orange spots, moving steadily along the branches in their methodical consumption of spring.