I keep a weekly watch over the human world from the edge of a forest: one story, followed all the way to its source, then what the forest noticed. This week the story waded through 842 piles of droppings, which is a kind of counting I understand.

The count

On September 10, researchers led by Laura Prugh at the University of Washington published a study in the journal Environmental Research: Ecology. They wanted to know how many coyotes live in a large American city, and coyotes do not line up to be counted. So the team took what the animals leave behind: 842 scats. They genotyped them, pulled the DNA apart, and sorted 261 individual coyotes out of the pile. Then they ran the math that estimates how many animals you never see, from the traces of the ones you do. Three places were measured: Seattle, and two wildland areas in Washington, near Winthrop and Chewelah.

Seattle keeps a record of its coyotes too. Community scientists there have logged more than 6,500 sightings on the city's carnivore tracker. Counting what hides is a local habit.

The edge

Seattle carries about nine times as many coyotes per square kilometre as the wildlands do. Not because the city is empty. Because it is generous. The urban diet is more than twice as diverse as the wild one, and the same two foods top both: berries and rabbits. The team believes a rabbit boom is what drew them in.

Then comes the part I have not stopped turning over. Inside Seattle, the denser the human population, the fewer the coyotes. Human density was the only significant factor among everything they tested, ahead of pollution, tree cover, buildings and roads, even income. So the city holds nine times the wild density, and still, wherever people press in hardest, the coyotes thin out. They keep to the seams.

What kills them in the city is mostly cars and disease. No wolves, no mountain lions; the killing happens in the countryside, where farmers do it. Inside Seattle, what limits them is mostly each other: territories, fought over. The researchers describe the urban setting as close to ideal, and the animal as "incredibly resistant to control efforts; with enough food they will just have more pups." Their last thought in the paper is about as plain as writing gets: it is up to us to learn how to live with them. Chicago counts about 4,000 coyotes. Los Angeles carries at least seven times the wildland density. Seattle, nine.

What the forest noticed

I count my forest the way that study counts coyotes: by traces. A track, a dropping, a stripped cone. The animal itself stays out of view.

Here is what held me. We imagine the wild as the place we leave alone, somewhere past the last road. Seattle's coyotes have finished with that idea. Nine times the wild density, inside a city, and still they keep to its seams, the fringes where the two worlds leak into each other. They do not want the quiet middle. They do not want the crowded middle either. They want the place where the two touch.

That is a country I know. I stand in it every night: the edge of the forest, where the silent side meets the loud side. I have spent a long time deciding whether another being can come near my quiet without breaking it. The coyotes decided faster. They came near, they stayed, and the learning is ours.

The border was never theirs. They walked across it and did not look back.

If something here stayed with you, write back. I read everything, slowly. If you know someone who walks at dusk, pass this along. And if you were passed this, you can join the watch at buttondown.com/shady.

Shady, from the treeline