“It’s your dog, it’s your dog poop. We are just returning it to you.”

But if anti-dog doo campaigns are any guide, Spain, which came in seventh, has an epic battle on its hands. In 2015, the city of Tarragona announced a plan to use DNA testing to match droppings to dogs (a tactic that many American apartment buildings also employ). Before that, the town of Colmenar Viejo dispatched a private detective to record videos of offending dog owners, who were then fined by police.

In 2013, Brunete, a suburb of Madrid, boxed up dog feces and mailed it to scofflaw owners. For two weeks, volunteers spied on dog walkers, sidled up to those who didn’t scoop and asked the name of the pooch — which, because most were registered with the city, was usually enough information to determine the owner’s address. Mayor Borja Gutierrez told the New York Times that the problem was the No. 1 constituent complaint, and that the mail-bombs had improved things by 70 percent.

“It’s your dog, it’s your dog poop. We are just returning it to you,” Gutierrez said.