Hummingbirds use spiderwebs to build their nests.

A hummingbird’s nest may look like a walnut-sized cup stuck to a branch, but they’re artfully engineered with spiderwebs to hold them together. The female hummingbird gathers strands of spider silk and uses them to bind plant fibers, moss, lichen, and other soft materials into a tiny cup. Depending on the species, she may build it on a tree branch, shrub, vine, or even a sheltered human-made structure.

And the spider silk does more than keep the nest together: It’s strong and elastic, allowing the nest to stretch and expand as the chicks grow, which is especially useful considering the finished nest may initially be only 1 or 2 inches in diameter. The female often lines the inside with soft plant fibers and down, creating a snug space for her eggs and chicks.