Hummingbird nest

Tiny nest (about 7-8 cm in width), covered in lichen.

From wikipedia:
Most species build a cup-shaped nest on the branch of a tree or shrub, although a few tropical species normally attach their nests to leaves. The nest varies in size relative to the particular species—from smaller than half a walnut shell to several centimeters in diameter.

Many hummingbird species use spider silk and lichen to bind the nest material together and secure the structure. The unique properties of the silk allow the nest to expand as the young hummingbirds grow.