According to this article from NC Cooperative Extension at NC A&T University about yellow-necked caterpillars, the caterpillars in my blueberry bush are in a feeding aggregation.

I’m not above taking caterpillars and tossing them into the field when they are threatening my crop, but since I already picked my last blueberries for the season, I wasn’t feeling so possessive about a few leaves. They do turn into pretty butterflies eventually.

I went to check on just how much they were eating this morning but they were all gone.  I did have a branch bare of leaves. They might have moved on, or they might have gotten picked off by the birds…