I have found several bird nests in the woods this spring, each made from different materials. One is tiny and full of paper birch bark and moss, another full of wide grass blades and bark from a grape vine. The most recent one I found is made from an outer layer of the mycelium in this photo. The lining is made of white pine needles. This photo above shows the dried, branching hyphae of a fungus that was decomposing the log on which it was growing. The mycelium made a sturdy net of tiny black threads that acted like a basket for other nest material. After a winter with lots of heavy snow, the nest is falling apart and was probably blown from whereever it was built.