In the case of bird’s nest fungi, spore pods (peridioles) develop within a covered fruiting body (peridium). Once the lid detaches, the mature pods are exposed. Raindrops turn the peridia into splash cups, propelling the pods several feet. The peridioles are covered with a sticky substance which allows them to adhere to whatever they land on. Eventually the pods dry out and the the spores are released.
Like other fungi, the bird nest varieties require certain limits of sun exposure, moisture level and temperature range as well as a desirable substrate. One of the species shown here appears to only grow on the decaying branches of red elderberry in the woods behind my house.
Those which find their way to conditions which meet their needs, go on to start the cycle over again.