Few people would feel up to the task of constructing a home from scratch, using only the materials they could carry. But birds possess an innate ability to build delicate nests from grass, twigs, or mud that regularly pass the most difficult test for any species: they cradle and protect the next generation.

Photographer and author Sharon Beals visited the California Academy of Sciences, the Museum of Vertebrate Zoology at UC Berkeley, and the Western Foundation of Vertebrate Zoology to photograph the nests featured in Nests: Fifty Nests and the Birds that Built Them (Chronicle Books, March 2011). This slideshow features some of our favorites.

Barn swallows inspired conservation movements in the 1800s, when they were routinely killed for their feathers, which were used to decorate hats. The mud-and-grass nests of the now-abundant barn swallow can be found clinging to the walls of barns, sheds, and bridges in North America, Europe, and Asia. This particular nest was collected in Manchuria.

Sightings of the colorful yet elusive spotted nightingale-thrush are rare. In the mountain forests of Central and South America, the female weaves its nest from moss, lichen, leaves, and grass.

Bank swallows nest in colonies, where males tunnel into sandbanks and then draw females into the burrows with ruffled feathers and displays of song. Once wooed, females will help finish the nest, bringing in grass, twigs, and feathers to line the holes.

The nests of Caspian terns can range from a simple hollow scraped in the sand to a more elaborate plot decorated with colorful shells, seaweed, and rocks. Both parents share the work of incubating eggs and feeding hatchlings.

Female hummingbirds bind their tiny nests together with spiderwebs. Though the iridescent birds are visually striking, their nests are expertly camouflaged; hummingbirds have been known to use bits of lichen, paper, and paint chips to give nests the right hue and texture to blend in with surrounding tree branches.

Young house wrens leave the nest roughly two weeks after hatching. Parents follow to care for the fledglings, so runts that don't fly away with their siblings are left to die.

The nests of pine siskins tend to be exceptionally well hidden. The cold-tolerant birds vary their habits according to the availability of seeds. In some cases, they start courting mates and nesting in the middle of winter.