Pipe Organ Mud Dauber Wasp Nest

Mud-dauber wasps nest on cliffs, walls and bridges with easy access to mud. They make their nests on smooth, vertical surfaces sheltered from sunlight and rain.

To make one, the female wasp shapes mud into a pipe and partitions it into a few "brood chambers". There she will lay eggs and stockpile several small spiders or a few large ones for her young to eat.

Before collecting mud, a female checks its consistency with her mouth; she tests quite a few sources before settling on one. Once she is satisfied, she lunges with her jaws spread out and scoops some mud. Then passing it on to her front legs, she again lunges and scoops some more, and finally flies away with the load.

With every load of mud brought thereafter, she makes a strip starting in the middle, working it downwards to meet the surface. A strip on one side is alternated with that on the other. The resulting nest has an inverted V-shaped striped appearance on the outside; on the inside it is made smooth.

A male guards the nest while the female builds it, and when she is away collecting spider-food for their unborn children.(http://www.bbc.com/earth/story/20160113-12-nests-you-wont-believe-were-…)