This is an ivory-billed woodpecker with a cross section of a cavity nest, a nest hollowed out within a tree.

This work was done for MITx and Dr. Lorna Gibson, professor of Materials Science and Engineering at MIT. For more information, see Built to Peck: How Woodpeckers Avoid Brain Injury and her associated edX course, 3.054x (Cellular Solids: Structures, Properties and Engineering Applications).