But it wasn't raindrops he was hearing -- it was caterpillar poop.
Robbins is a researcher at Kansas University.
Robbins had been looking for birds at K-U's Fitch Natural History Reservation north of Lawrence.
He says when the sun came up he saw thousands of caterpillars in the branches.
Robbins tells the Lawrence Journal-World those caterpillars will soon turn into more Hackberry Emperor butterflies than he's ever seen.
He figures the mild winter contributes to the coming butterfly explosion.
