A recent analysis suggests the design of some birds' nests varies because of culture, rather than genetics or environmental conditions.

Birdsong can have "accents," and crows can teach one another to use tools. Now there's another reason to suspect the creatures have their own distinct cultures: nest-building practices unique to different groups of birds.

A recent analysis in the journal Science suggests the design of some birds' nests varies because of social learning, rather than genetic relatedness or environmental conditions.

To determine whether different groups of birds have different architectural styles, researchers observed white-browed sparrow weavers -- small birds that live, and build their nests, cooperatively. They studied 43 groups of the birds living in a nature preserve in South Africa, looking at 397 roosts and 47 nests in all.

To learn more about their nest-building practices, researchers looked at footage of the birds building their nests and roosts, then tagged and measured the structures. They also looked for variations in structure and noted other variables including local weather, the size of the birds building the nest and the height of the trees where they nested.

Their analysis found that different groups of birds developed their own recognizable nest structures, and that belonging to a group of building birds explained more nest variation than other factors such as a bird's size, local weather or their DNA. Instead, the researchers conclude, "Birds that live together also build together and this ... creates a group's specific architectural style," they write.

The research adds to a growing body of evidence suggesting humans aren't the only ones with cultural traditions. Other studies suggest that animals engage in social learning and cultural behavior; for example, bottle-nosed dolphins are thought to teach one another to use marine sponges to hunt and to prefer other dolphins that use sponges as tools over those that don't.

What kinds of behaviors influence animals' architectural choices? That will take more research to unravel, the team suggests, calling for more studies on cooperative birds, bees and other creatures that build.

Architectural traditions in the structures built by cooperative weaver birds

Science