A gaggle of geese runs riot in the Hof van Delft Park. They honk, they hiss, they harass, and - it's hard not to notice - they scatter droppings everywhere.
Soon, a lanky stranger comes to impose order on this chaos. He strides straight toward the center of the flock, a place few would dare to tread, especially wearing clean shoes.
They call him "The Goose Whisperer," and he has a job to do.
Martin Hof has become a minor celebrity here, in part for his ability to communicate with fowl, which some say borders on the magical.
And while there's something special, and a little comical, about watching him at work whistling, talking, and yes, whispering to the birds, there's more to this than meets the eye.
At age 23, Hof has developed an unusual approach to managing urban geese populations that is gaining adherents in the animal-friendly Netherlands - the first country in the world with an animal rights party in parliament.
"It's all about respect for the geese," he says earnestly.
The main problem at the Hof van Delft, and most parks, is that the birds have been allowed to overbreed and are clashing with the humans whose territory they share.
But rather than culling, he finds new homes for the geese, dividing them along family lines to reduce the trauma of the move. On the other side of the equation, he works with the humans who consider the geese as either pets or pests.
That means discouraging feeding the animals and educating city workers on preventing the birds from overbreeding in the first place.
"They call them 'silly geese', but they're so smart, they learn everything," says the pony-tailed goose whisperer. "We teach them, we silly people, to break through their natural barrier whenever we come up to them with bread."
After one goose lunges at a passing jogger, attempting to bite his legs, Hof approaches the troublemaker for a little chat. To show he's a friend, he uses his arm to mimic a goose head bobbing up and down. Their conversation is too quiet to hear, but the goose appears calmed, and waddles off to rejoin his group.
Hof says the goose wasn't being aggressive, she was just startled that a stranger ran right into her personal space without warning. That hissing noise geese sometimes make? "Pure stress," Hof says.
Incidents become more common when geese are fed by parkgoers, Hof says. Eventually, children get nipped, neighbors complain and birds are culled.
Hof says that's wrong, and unnecessary.
To begin with, he keeps a database of a hundred or more farms or parks that actually want a few geese. City workers usually don't have the time for such niceties.
They slaughter indiscriminately, which is also cruel to the birds that remain, Hof says. Geese are generally monogamous, and a pair may live together forty years.
Partners that are suddenly split may never recover from the shock. "Some literally die of loneliness," Hof says.
For those skeptical about the emotional lives of geese, there's a more practical reason: survivors may call endlessly for missing family members, increasing noise problems.
After an experience saving a goose caught in a fishing net when he was seven years old, Hof became fascinated with the birds. Sixteen years later, he can usually identify families at a glance.
But he carries out various tests to be sure. He walks into the middle of a group, whistling, then observes their reaction.
"Just when I drove them apart, you saw that families started calling each other ... they say 'hup hup hup hup: Here I am! Where are you?"'
Individuals take a little longer to get to know. But at his shelter in the town of Coevorden where they live out their days, Hof fluidly names dozens by sight: Brenda, Carmen, Aida, Flago, Sunny, Pablo, Caesar ...
Hof says half his job is managing people.
Joke Fransen, walking her dog, complained vociferously about goose droppings.
"It's getting worse every year," she said. "Put them in a pan or make pate out of them, I say."
But after a few minutes speaking with Hof, she's beaming and laughing too. She likes the geese, just not so many, and she wholeheartedly prefers relocation to culling.
To make Hof's strategy work long term, city workers also have to learn about bird birth control.
It's not complicated: every two weeks during the late spring, a worker needs to check near the edges of waterways for eggs. Smearing them with corn oil is an effective and nonpolluting way to prevent unwanted goslings.
Gerard Zwart of the Amsterdam's public health agency, which has hired Hof's company for several projects, says the city has been so influenced by his thinking it plans to rename its "Vermin Control Service" to the "Nature Management Service."
Capturing geese for transport is "the most stressful part," Hof says. He kisses each on the back of the neck before loading them onto his "Royal Geese Carriage" that will whisk them away to a better life.