LEILA FADEL, HOST:

Good morning. I'm Leila Fadel. In 20 years of pest control, Nick Castro had never seen something so strange. After getting a call about an insect problem at a California home, he cut into a wall to find tens of thousands of acorns. Castro thinks it was woodpeckers that spent years collecting, storing and snacking on the acorns. And one of the birds, according to Castro, is a little bit of a pack rat, but maybe it's just more of a bird hoarder. It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.