Purple Martins Call Nashville Home. Some Wish They Wouldn't

I had never seen so many birds in one place. Gripping the umbrella I hoped would protect me from droppings, I stood in the empty parking lot of Nashville’s Nissan Stadium, home of the Tennessee Titans professional football team. Mesmerized, I stared at the sky filled with purple martins and watched them concentrate in graceful eddies, swooping and swirling as if each group was its own entity.

It was after sunset on a July evening in 2024, and I was witnessing a roost, a natural wonder. For several weeks before their migration to South America for the winter, these martins would spend their nights packed into trees next to the stadium before dispersing to hunt for insects during the day. Roosts are found in urban and rural settings and may range in size from a few thousand to hundreds of thousands of birds. At its peak, this roost, separated from the city’s downtown skyline by the Cumberland River, would reach an estimated 150,000 martins or more.

In 1996, the nonprofit Purple Martin Conservation Association first detected purple martins in Nashville on weather radar. Over the following years, the martins, thought to number in the tens of thousands during this time, roosted next to an interstate and in a business park, moving when their trees were removed or pruned.

But everything changed in 2020. That summer, they chose to roost at the Schermerhorn Symphony Center in the heart of downtown Nashville. And there were no longer tens of thousands of birds; it’s thought as many as 150,000 purple martins joined that year’s roost.

A rare urban roost

The birds’ choice made the Nashville roost unusual. “There's not that many roosts that are located in very public areas like that,” said Tara Dodge, PMCA’s Education and Member Services Director. So how does a city deal with an annual influx of 150,000 birds into its downtown? For almost five years, Nashville has tried to answer that question and has become — whether it likes it or not — a case study in the dynamics between a city and its birds.

Nashville’s struggle with purple martins is part of a wider trend of human-animal conflicts. “There’s more and more conflicts because there’s more and more people; really, that’s the nub of the issue,” said Barry McMahon, an associate professor at University College Dublin studying wildlife conservation and zoonotic epidemiology. In 2023, he and some colleagues published an article exploring international examples of human-bird conflicts in areas such as agriculture, resource management, and collisions between birds and man-made objects and structures. They also examined factors that complicate these problems including the large number of people involved, history between parties, and the effect of differing priorities on perceptions of the issue.

The scenario described by McMahon and his colleagues describes Nashville’s situation since 2020. Despite their differing views on whether the roost is a problem and how to manage it, a myriad — and changing — group of Nashville leaders must work together in response to the martins’ arrival. These discussions have resulted in frustrations, compromises, landscape alterations, and new partnerships and initiatives.

The Symphony first realized purple martins were roosting on their campus when Alan Valentine got a call at home from the mayor’s office. Valentine, CEO of the Symphony, learned that a group had been watching the birds settle in for the night at the Symphony building when a pest control truck arrived. Symphony employees thought the birds were European starlings and had hired the company to spray grapeseed oil to drive them away. But the group explained that these purple martins were protected by the Migratory Bird Treaty Act, and the pest control employees left.

A self-described nature and bird lover, Valentine began to learn about purple martins and discovered that the trees at the Symphony, grown close together like a “gigantic hedgerow,” were perfect for the birds. But the situation wasn’t perfect for Valentine. The trees that held the martin roost night after night were damaged. The birds had mottled the concrete plaza and sidewalks with droppings which clogged drains and got into the fountains. Valentine described the smell of the waste as “almost nauseating” and said it even washed inside the building during rain. The side of the building was also spotted with waste, and Valentine worried that repeated power washing would damage the limestone facade.

The purple martins returned in the summer of 2021. Although the Symphony had been closed due to the pandemic during the 2020 roost, it reopened in August of 2021. Valentine worried about the audience having to navigate the roost to attend performances.

The cost of clean-up was also a burden. The Symphony, a nonprofit, had already lost millions during its 17-month COVID closure, although it did receive some government grants and loans to mitigate the loss. According to Valentine, it cost more than $100,000 to clean up the campus after two years of roosts; organizations including The Nature Conservancy helped with this cost.

The birds’ waste has been a particular point of disagreement among those involved. Valentine and Kendra Abkowitz, Senior Director of Sustainability and Resilience within the Nashville Mayor’s Office, both claim that the waste is a public health hazard. “Every single year, somebody from the city brings up this excuse for why the birds shouldn't be there,” Laura Cook said. Cook is a biologist and coordinator of Nashville’s Warner Parks Bird Information Research and Data program. She understands why the Symphony would not want to host the birds but takes issue with the claim that their waste is harmful. “As of right now, there has never been a documented case of spread of disease from a purple martin roost to humans,” she said.

PMCA’s Dodge agrees and says that when people express concern about the health implications of bird waste, they are usually thinking of European starlings whose waste can cause histoplasmosis, a respiratory disease. While purple martins can suffer from diseases including avian pox, those diseases are not transmitted to humans. At this point, there have not been any cases of purple martins testing positive for avian influenza. 

For Cook, the birds’ presence is an opportunity to learn more about them. “I would say we would embrace them with open arms,” she said, describing her ideal response. “I mean it is truly a migration phenomenon that urban areas do not get to experience.” In 2021, she and her team began tracking the purple martins that nest in Warner Parks by attaching tiny transmitters to them; a network of international receiver stations detect the radio signals the transmitters emit. The same year, the Warner Parks team worked with The Nature Conservancy to erect a receiver station on a skyscraper next to the Symphony just for the duration of the birds’ stay and has continued doing so each year. Cook’s goal was to discover whether the purple martins hatched at the park join the large downtown roost. She learned they did and was also surprised to see how far the birds travel each day searching for insects before returning to the roost each night; some even made it to southern Kentucky. In 2022, Cook and her team expanded their efforts to two more locations to further their research.

Meanwhile, Valentine found himself at the center of a controversy. The Symphony’s neighbors were complaining about the martins, and he received angry letters. Bird conservationists wanted to protect the birds, and tree conservationists wanted to ensure the trees were maintained. “Everybody was yelling at us from every direction, and there was no consensus,” he said.

Deterrence

So, before the martins arrived in 2022, an agreement was reached among the interested parties on how to respond to the anticipated roost. Prior to the birds’ arrival, the Symphony cut down 31 of its trees, non-native Chinese elms. They then planted 24 trees, including a native species, which Valentine expects will have bigger canopies than the elms. Other trees historically used by the martins near the Symphony — but on public property — were pruned. Everyone agreed that if fewer than 100 martins began roosting in the remaining trees, they would be immediately cut down. But if more than that had begun roosting, the trees had to be left alone. To deter the martins, a falconer was hired, and recordings of crows were played. The Symphony also donated to Warner Parks to help the program purchase more radio transmitters for tracking the martins and donated to plant more trees downtown. The city assigned some of its street cleaning crews to clean up after the birds, a practice they continued for future roosts.

Their efforts worked; the martins didn’t roost at the Symphony in 2022. The Metro Parks department tried — but failed — to entice the martins to roost at a Metro water facility using lights and purple martin recordings. Instead, the martins ended up less than a mile away from the Symphony in trees under a pedestrian bridge spanning the Cumberland River.

But in 2023, the purple martins returned to the remaining trees near the Symphony, the largest roost Nashville had seen. About 170,000 birds are estimated to have joined the roost. But that’s not the only notable difference. In the spring of that year, Nashville officially joined the U.S. Fish and Wildlife’s Urban Bird Treaty Program. The idea to join came about after the 2022 meetings to decide what to do about the martins at the Symphony; a group including Cook wanted to be more proactive in their conservation efforts. The UBT agreement, signed by the Mayor’s office, established a partnership between Nashville and the USFWS to benefit local birds by mitigating urban dangers, educating urban communities, and protecting urban habitat. Yet, in the spring of 2024, the city, led by a new mayor, cut down the trees on city property that still remained near the Symphony and replaced them with native trees.

When the birds returned to Nashville in 2024, they did not roost at the Symphony. For his part, Valentine is pleased with how the purple martins were handled. “Is everybody happy about it? Probably not,” he said. “But I think most of the people involved recognize that we tried to create a balanced response that took everybody's concerns into consideration.”

The martins tried roosting in several locations that year. About 10,000 martins chose a narrow downtown street. The city sent its arborists to inspect those damaged trees every day concerned that falling branches could pose a liability risk. According to Cook, there was talk of cutting down those trees as well. Frustrated, she encouraged everyone to be patient; she knew that that location could never have accommodated the entire roost. “You can't say you're an Urban Bird Treaty City, and then as soon as it's not convenient, do something like remove the birds from those locations,” she said. Eventually, the birds left that street. Some of the martins roosted at the pedestrian bridge again, but most roosted at the Titans stadium where I saw them.

Acceptance?

And now Nashville waits for the 2025 roost. Will the purple martins return to the stadium? Some of the trees they used before have been cut down, their survival in doubt due to damage. Also, construction of a new stadium next to the current one is ongoing. Abkowitz says it’s difficult to anticipate if the city’s response will change. “It's a slightly different issue, slightly different timeline, slightly different set of stakeholders and challenges that we're encountering each year,” she said.

Cook hopes the Purple Martin Taskforce will reconvene this year. The taskforce, an initiative of the city’s Urban Bird Treaty agreement, began last year as a way for interested groups to monitor and plan for the arrival of the roost. She’d like the group to learn from past years, identifying both successes and areas needing improvement. She also hopes there will be more “watch parties”, an effort by Warner Parks and others started last year to encourage the public to see the roost. She hopes that with more people coming to enjoy the martins, the city will hear more positive feedback about these birds. “We had people coming from other states to visit Nashville just to see the purple martins. And I just think that there is an opportunity for us to take advantage of this and turn it into something positive, instead of trying to fight against nature,” she said.

Maggie Gigandet is a freelance writer focusing on the outdoors and people with interesting passions. Her work can be found in The Atavist, Backpacker, Smithsonian Folklife, and Atlas Obscura. Maggie volunteered with Warner Parks as a roost monitor and is a member of the Tennessee Ornithological Society. For more of her writing, please visit maggiegigandet.com.