The Desert’s Coolest Commune

No one understands communal living like the sociable weaver. The small, straw-colored birds transform the hot, dry deserts of South Africa into a bustling metropolis—the avian equivalent of Cape Town. Weavers are desert engineers that dwell in sprawling, spectacular community nests that may house more than a hundred birds. Some nests can weigh as much as 2,000 pounds. Weavers build these nests in anything that will hold them, including trees and telephone poles. These communities are their cities, protected from predators and frost—as well as the prying eyes of humans, as we can’t help but want to look inside.

Despite their name, sociable weavers do not weave. They thatch, gathering sticks and dry grass to insert into the sides of the nest to keep it sturdy and insulated, filling in cracks that may have formed over time. If these nests are to survive, they must be tended to by all the weavers—like Sagrada Familias constructed over lifetimes. The nests can last for several generations, often longer than a century, with young weavers tending to structures their great-great-great-great-great-great-great-great-great grandparents built (weavers can live for 10 years). The nests don’t just outlive the birds themselves; they can outlast the creatures that roam around them: lions, cheetahs, hyenas, wildebeest, springbok, snakes, and attractively coroneted secretary birds. These larger safari stars live and die around these communities, perhaps experiencing them as eternal parts of the landscape as opposed to anything crafted by claw.

From outside, the nests almost appear honeycombed, with small entrances hollowed in from beneath, each representing a private entrance for a sociable weaver or two—most likely a breeding pair. If you shrunk down to fit through the ten-inch-long and one-inch-wide entrance hallway, you would find walls padded with soft plant material that feels almost like down. These make plush pads for birds who lay up to six eggs at least four times a year and raise their chicks until they are old enough to tend to the nest. Life may be onerous for the adult weavers, spent collecting grass and stuffing the nest, but it is dangerous for baby weavers, 70 percent of whom fall prey to snakes that lurk below. That number seems bleak, but without the nest, it would surely be worse. The spiky straws extruding from the bottoms of each entrance to the nest offer the weavers ample protection against the cape cobras and large-eyed tree snakes who might otherwise climb into the nests.

Sociable weavers are such great architects that other animals want in on the real estate—including Kalahari tree skinks, barbets, wasps, and geckoes. Scientists have even discovered a new genus of small arachnids called pseudoscorpions that live in the nests and feed on other invertebrates that take shelter there—and may even hitch rides to new nests in the plumage of the weavers. Sometimes, other birds move in. Small birds like red-headed finches and rosy-faced lovebirds stop by to breed. Big birds such as pygmy falcons take up permanent residence in the nests, to the weavers’ great chagrin. The falcons offer their services by scaring away snakes but occasionally may chomp on a weaver or two (which still makes them better than some neighbors I’ve had). Giant eagle owls may take up roost on top of the nests, and barn owls may wedge into the nest’s cavities. These birds, at least, leave the weavers alone.

Desert life is hot, dry, and harsh, but the nest keeps things temperate. When summer heat simmers over 110 degrees Fahrenheit, the weavers’ nest offers vital shade and retains moisture that can be hard to find. When frost takes over in the winter, with temperatures dropping to 14 degrees, the nest stays about 60 degrees warmer than the outside air, and the birds huddle together to keep warm. After nestlings fledge, the young birds rarely leave. Their parents grew up building and repairing that nest, and the next generation sticks around to help in all the ways they can. Oases like these are rare in the desert.

The weavers live their lives without much routine. When dawn breaks, the birds begin speaking to each other, calling to their neighbors in nearby nest chambers. Near sunrise, the weavers peek out and may even begin to stretch their wings. They flock to their feeding grounds to feast on seeds and insects throughout the day, taking a siesta at midday, when the sun is at its highest, under bushes or within the nest. As the sun sets, they return to the nest to roost for the night, perhaps bringing a twig or two to keep the nest strong for another century.