Bird’s nest showing traces of architectural “culture”

Bird’s nest showing traces of architectural “culture”

Written by Gennaro Tomma

From long, winding migratory flights to complex songs and clever tool use, many bird behaviors are known to be socially transmitted and persist across generations, leading scientists to describe this as an animal’s “culture.” It is defined as Now, research suggests that culture may also play a role in the structure of birds.

Researchers analyzed more than 400 structures built by 43 different groups of white-crowned sparrow weavers living in the Kalahari Desert in southern Africa. These birds live in groups, and the entire flock works together to build nests and multiple roosts from the grass. The dominant female of the group then lays eggs in a nest with a long, tubular entrance. In a U-shaped roost with both an entrance and an exit, individual birds sleep close together.

Scientists have discovered that different groups of birds build very different tube structures, even those that are only a few meters apart from each other. The biggest difference was “how short or long the structures were,” said study lead author Maria C. Tero-Ramos, a cognitive ecologist at the University of Hull in the UK. Tube width also varied between groups. Furthermore, each group maintained the same architectural style over time and adapted to this style when outsiders joined.

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To find out why groups formed differently, the researchers looked at factors that determined nest size and shape in particular bird species, including weather conditions, tree height, individual body size, and genetic relatedness. We analyzed the factors contributing to this. (For example, if closely related birds build similar structures, one might infer that there is a genetic component.) But none of these factors affect how the Kalahari sparrow builds its nests. The researchers reported that it did not appear to play a relevant role in shaping the
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“So you say, ‘So what’s left?'” Tello-Ramos explains. She and her colleagues proposed that cultural transmission may be the key to nesting. “Our paper gives us very good clues that it might be possible, although the experiments aren’t quite there yet,” she says.

“These are important and understudied questions,” says Christina Leal, an evolutionary biologist at Princeton University. She is not convinced that the data from this study is enough to completely rule out genetic influences. “They can’t really look at the effects of genetic differences, for example, because they don’t have really good genetic information for all the individuals in these groups,” she says. “I think there’s a lot of work left to do, and I think this paper will have a really positive impact on future research.”