We’ve written about dung before, when it came to beetles rolling it for the poop’s role (ha) in their life cycle, and when it’s been used for recycled paper, and even household cooking gas derived from biodigested manure. Now, we’re learning via Audubon Magazine about another use for the dried doo, and we figured that would be a good time to share about another interesting excremental story from the natural world, which happens to be the fastest moving organism, in a sense.

Both the Black Lark, a bird species found in Europe and western Asia, and the genus of fungi called Pilobolus, more widely distributed around the world, have to deal with something called the Zone of Repugnance when it comes to dung. Although the ornithologists in the Audubon article aren’t quoted using this phrase, it is accepted in mycologist parlance for those who study livestock excrement or something related to it: animals will avoid eating grass or greens in an area where fecal matter is present. Around every pile of poop is a perimeter that the grazers try to not chew on. Black Larks take advantage of that fact to build their nests in no-step zones, and Pilobolus need to shoot their spores behind enemy lines. Matt Soniak, for Audubon:

A few years ago, ecologist Johannes Kamp was on the Kazakh steppe studying the breeding ecology of theBlack Lark. While searching for the birds’ nests in the high grass, he realized that all he had to do was flush the females out and look for nearby animal dung. Wherever there was horse or cattle dung that looked slightly “arranged,” he usually found a nest.

This wasn’t just coincidence. Kamp observed female larks carrying dung in their bills, sometimes fetching more than a hundred pieces over the course of a few days, and arranging them in rings around their nests. “They arrange the dung so orderly and in such a nice shape that it really looks like pavement, as you would lay at your front door,” says Kamp’s collaborator, ecologist Thijs Fijen.

Lots of birds add odd items to their nests. Bowerbirds are known for using sticks, berries, and even coins as decorations to attract mates, for example, and urban sparrows and finches work cigarette butts into their nests to ward off parasites. Dung seemed like an odd choice of building material, though, and a costly one. Finding the dung and constructing the rings takes time and effort, leaving the larks exposed to predators.

Fijen and Kamp suspected there must be some benefit to the dung “pavements” to justify those costs. So, with a team of researchers from Europe and Kazakhstan, they returned to the steppe to figure out what it was.

If this story is interesting, keep reading it here. Learn more about the hat-throwing fungus here.