What is unusual for this species is the temperate rainforest habitat of the Squamish Estuary in which this caterpillar is living.

It was feeding on Picea sitchensis (Sitka spruce). The second photo on a red alder leaf with a black cottonwood bud for scale, shows the caterpillar in the hand of the elementary school student who spotted it.

Is this another sign that our climate is getting drier?