The ovenbird constructs a free-standing domed nest by adding mud pellets in a set pattern.
Video
Image: Charles J. Sharp / Wikimedia Commons / CC BY - Creative Commons Attribution alone
Physically Assemble Structure
Living systems use physical materials to create structures to serve as protection, insulation, and other purposes. These structures can be internal (within or attached to the system itself), such as cell membranes, shells, and fur. They can also be external (detached), such as nests, burrows, cocoons, or webs. Because physical materials are limited and the energy required to gather and create new structures is costly, living systems must use both conservatively. Therefore, they optimize the structures’ size, weight, and density. For example, weaver birds use two types of vegetation to create their nests: strong, a few stiff fibers and numerous thin fibers. Combined, they make a strong, yet flexible, nest. An example of an internal structure is a bird’s bone. The bone is comprised of a mineral matrix assembled to create strong cross-supports and a tubular outer surface filled with air to minimize weight.
Birds
Class Aves (“bird”): Eagles, hawks, sparrows, parrots
Birds are evolutionary engineering marvels. They are descended from dinosaurs, but are far from our idea of heavy, scaly reptiles. Of the specific adaptions that set them apart, most notable is flight—although some mammals can fly, birds take the prize for abundance in the skies. Many birds have hollow, lightweight skeletons and specially-designed wings to help them stay aloft. They also have feathers made of keratin that help them stay warm, attract mates, and improve navigation and aerodynamics in flight. In contrast to their dinosaur ancestors, they lack true teeth and have replaced them with specialized beaks and bills.
References
-
“In about two weeks these diminutive birds manage to work two thousand pellets of mud, weighing about ten pounds in all, into an impressive dome…The oven’s construction involves building a rather ordinary but oversized adobe cup on the branch. This is then built up to make a sphere with a circular opening on one side, close to but not directly over the branch. Adding the mud pellets and smoothing them out without risking a collapse of the domed roof as it curves inward must require considerable care; the procedure employs behavior highly modified from that used for the cup…The birds construct a curved internal wall about three-quarters of the way toward the roof, creating an entrance chamber between the door and the nest cavity. The indirect entryway becomes a severe obstacle for predators, and the smooth concrete-like dried mud itself repels attacks.” (Gould and Gould 2007:185)
