SPIDER ASSISTANCE
The material that often serves as the glue in many bird nests is made by an entirely different animal. The strong silk of spiders’ webs is often collected by birds and incorporated into the twig architecture to hold loose components together. Small birds, such as kinglets and hummingbirds, hold spiders’ webs in their beaks and use them to wrap silk around the edge of their nests.
Because a spider’s silk is made from large proteins, the material is stretchy and sticks to the nest. The flexibility of the webbing provides leeway for the nest’s structure to move slightly as bird nestlings grow and bustle for space and food. In other cases, spiders themselves are used by birds. House wrens, for example, steal spider eggs and place them in their nests. Based on laboratory experiments, scientists suspect that these spiders serve as pest control for the nest. When they hatch, they feed on mites that are parasitic to the young birds.