Birders everywhere know about the spring spectacle of hundreds of thousands of Sandhill Cranes on Nebraska’s Platte River, but do you know about the Cornhusker State’s other spectacle of migratory birds? Tens of thousands of Purple Martins gather every evening from late June through early October as they begin their fall migration toward Brazil.
Unlike the cranes, however, you won’t find the martins in farm fields in the sparsely populated middle of the state. They roost in a handful of ash trees next to the University of Nebraska Medical Center in Omaha, the state’s largest city. (Here’s a Google map of the exact location.) On a visit to Omaha, my hometown, my family and I stopped to watch the birds one evening last week.
It’s an incredible sight. In the last hour or so of daylight, huge flocks of martins begin to show up, seemingly out of nowhere. They circle over the Med Center, fly up into the sky, and dive toward the trees. A spiraling vortex of the dark songbirds may form. Sometimes a huge flock will shoot out of one tree and into another or will take to the sky once again.
Here and there, starlings and grackles join in the mix, but mostly, it’s martins raining down all around. The scene is chaotic and thrilling. My daughter wondered how the birds avoid crashing into each other. We were chatting with Justin Rink, one of the birders who discovered the roost in 2007 and continues to observe it regularly; he says no one knows how the birds manage to avoid mid-air collisions. “We have lanes for cars and still have crashes, but the birds have no lanes and do just fine.”
In the last several minutes of daylight, most of the birds begin to settle into the trees, then hundreds more show up, making their way toward the roost. Are they latecomers? Are they simply taking one last lap up from the trees and around the neighborhood before settling in for the night? With all the commotion, it’s impossible to say.
In this short video I took at the roost a few years ago, you can get a glimpse of the scene:
When darkness falls, the sky show is over, but the martins make a raucous chatter from their night roost while cars and the occasional ambulance pass by below.
On the night I visited, Rink estimated 20,000 martins were present. By late August, he expects the number to peak at 60,000 or more.
He said the birds probably chose the site because the tall hospital buildings immediately east and south of the trees create a windbreak. And across the street sits a low-profile school building with a flat roof that appears to offer an easy line of sight for the birds’ comings and goings.
Several years ago, lots of martins would hit windows on the neighboring buildings and a skywalk, but the number of window strikes is down considerably thanks to large banners that hang in the windows when the martins are present.
The roost site seems secure enough for the birds. Rink is most concerned about the potential that the invasive emerald ash borer will eventually reach Nebraska and cripple or kill the birds’ ash trees. To date, the insect has been detected in eastern Iowa and in the Kansas City, Missouri, area.
Of course, Omaha isn’t the only place to see a huge martin roost. Louise Chambers of the Purple Martin Conservation Association says you can find roosts in:
• Richmond, Virginia
• Lake Pontchartrain, New Orleans, Louisiana
• Presque Isle State Park, Erie, Pennsylvania
• Wichita, Kansas (still active but disrupted by tree pruning)
• Maurice River Township, New Jersey
• Mann’s Harbor, North Carolina
• Portage Lakes near Akron, Ohio
This isn’t a complete list, of course; you can find more roost sites through the PMCA’s Project Martin Roost, an effort to document roosts throughout the bird’s range. Late-summer martin roosts are thrilling natural spectacles. I highly encourage you to visit one! — Matt Mendenhall, Managing Editor
Watch for our December issue
Pete Dunne writes about the Purple Martin colony in his hometown, Mauricetown, New Jersey.