Thorny Oyster
Lime (a calcium compound) is used in human-home construction, but sea creatures such as this thorny oyster in Thailand rely on it as well; in fact, sea organisms have been building body shells from lime for estimated 600 million years.
Hummingbird
A Steely-vented Hummingbird nest in Central America is made from plant fibers, moss, and animal hair. It’s well camouflaged in a shrub, bush, or tree, and is built to stretch to almost double its size as the chicks grow. Only the females are involved in nest-building.
Reed Warbler
True to her name, the Eurasian Reed Warbler builds her cup-shaped nest on reeds; both mom and dad incubate and feed the babies. Unfortunately, these elegant dwellings attract unwanted house guests: European cuckoos like to deposit one of their own eggs here, leaving the “foster parents” to nurture their newborns.