CURWOOD: It’s spring time here in the Northern Hemisphere and that means many birds must soon get down to the serious business of nesting. But as BirdNote’s Michael Stein reports, when it comes to building a nest the sociable weaver takes the cake.

BirdNote®
The Sociable Weaver's Colonial Nest

When it comes to nests, common sense would suggest that if you’re a big bird, you build a big one — a small bird, a small one. But in fact, some species of smaller birds build large nests. None, though, build anything like the huge, communal, structures of Sociable Weavers in southern Africa’s arid plains. These House sparrow-sized birds often live in accommodations with room for up to 500 birds.

Made from stiff grass, they’re relatively cool during the intensely hot day and relatively warm during the very cold night. A colony is made up of hundreds of individual nests clumped together. Attached to acacia trees or utility poles, they look like haystacks suspended above the earth. Each pair or family of Sociable Weavers has its own access hole and tunnel into a chamber within the larger complex.

Some structures have persisted for more than 100 years, with constant occupation by succeeding generations of Sociable Weavers.

One drawback of these nest structures is their weight: up to a ton when dry, even more when wet. They’re so heavy they can break their supporting branches and go crashing to the earth below.

I’m Michael Stein.

CURWOOD: For photos migrate over to the Living on Earth website, loe dot org.