Maybe you’d never heard of purple martins until last year when the roost of more than 100,000 migrating birds was nearing eviction from trees around Nashville Symphony.
They’re considered the largest swallow at about eight inches in length. At the symphony, they would swirl around in something like tornadoes of birds until they would land for the night — sleeping shoulder-to-shoulder on branches.
“Nashville has hosted a very large purple martin roost for well over ten years,” says bird biologist Melinda Welton. “The first big roost that was found using weather radar. You can actually see the Martins leaving the roost because they are very large drops of water.”
When researchers are looking for locations where large groups of birds sleep, that’s one strategy – looking at weather radar. Melinda says when the birds take off in the morning, they all go in different directions at once — making a “donut” shape on a weather map.
For the last two years, these birds have favored the symphony as roosting grounds. Since the symphony’s trees have been recently been removed or deeply pruned, the birds no longer find a resting spot there. But where did they go? That’s what Melinda and other local researchers are trying to find out.
She says the city has pledged to plant many more trees downtown than the ones they removed.
“It’s great relief to the people who love trees in Nashville. To the symphony. To the bird people everywhere,” she says. “Everyone wanted those trees to remain. And I think the best compromise has been met. We’re going to watch to make sure that what’s been done is enough to encourage the birds to find another place to roost before they go to the upper Amazon.”
On a Wednesday night in July, Melinda is waiting out near Jefferson Street bridge gazing at the sunset sky around 3 trees. They’re Lacebark Elms — the same kind the martins were roosting in at the symphony.
“Most of the birds start coming in about 8:20 (p.m.), and then they’re mostly all in the roost by 8:40 when it gets dark,” she says. “It’s a bit like chaotic smoke, and they get lower and lower until they start going into the trees. But hopefully tonight we’ll see them at a great distance in the sky before they start coming into the trees.”
But 8:20 p.m. comes and goes. No birds. Melinda stares into her binoculars. Looking in all directions.
“I’m not even hearing or seeing starlings,” she says. “I have no idea what may have happened. Something’s happened to the roost.”
She wonders out loud if fireworks could have scared them off — but then says folks have seen them since July 4. She even asks nearby police officers nearby if they’ve seen the missing birds. No luck.
Finally, she sees a few Martins. But they’re acting strangely. About 40 birds took one pass at the trees and then flew off.
“How curious,” Melinda says, “we’re witnessing something that has not been observed in Nashville before.”
The sun has set, and it’s 8:40 — the martins should be settled into bed for the night. It looks to be a bust, if not a melancholy mystery.
Before giving up, Melinda steps toward the trees just to hear if anyone may have slipped in under her watch. And right as she steps near the canopy, in come hundreds of Martins.
“That’s the spectacle you were hoping to see,” she says. “They’ll swoop around and then they’ll settle into the trees.”
Over the next 20 minutes, birds keep coming in. Sometimes a couple dozen at a time, sometimes a couple hundred. All in the dark.
“Of all the roosts that I’ve watched in Nashville,” Melinda says, “that was the most curious display I’ve seen.”
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