Birdwatchers the world over know the springtime spectacle of hundreds of thousands of sandhill cranes on Nebraska’s Platte River, but do you know about Cornhusker State’s other migratory bird spectacle? Tens of thousands of purple swallows congregate each evening from late June to early October as they begin their fall migration to Brazil.
The Martins fill the sky in Omaha, Nebraska. Photo © 2013 Matt Mendenhall
Unlike cranes, however, you won’t find martins in farm fields in the sparsely populated center of the state. They perch 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.) While visiting Omaha, my hometown, my family and I stopped for birdwatching one evening last week.
It’s an incredible sight. During the last hour of the day, huge flocks of martins begin to appear, seemingly out of nowhere. They fly over the medical center, soar into the sky and dive towards the trees. A spiraling vortex of dark songbirds may form. Sometimes a huge herd springs from one tree and into another or flies up to the sky again.
Here and there, starlings and grackles join the mix, but above all, it’s martens raining all around. The scene is chaotic and thrilling. My daughter wondered how birds avoid crashing into each other. We were chatting with Justin Rink, one of the ornithologists who discovered the roost in 2007 and continues to observe it regularly; he says no one knows how birds manage to avoid mid-air collisions. “We have lanes for cars and there are always accidents, but the birds don’t have lanes and are doing just fine.”
During the last minutes of daylight, most of the birds begin to settle in the trees, then hundreds more appear, heading for the roost. Are they latecomers? Are they just taking one last ride through the trees and around the neighborhood before settling in for the night? With all this excitement, 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 martens chatter hoarsely from their nocturnal perch as cars and the occasional ambulance pass below.
On the evening of my visit, Rink estimated that 20,000 swallows were present. By late August, he expects the number to peak at 60,000 or more.
He said the birds likely chose the site because the large hospital buildings immediately east and south of the trees create a windbreak. And across the street is an inconspicuous school building with a flat roof that seems to provide an easy line of sight for birds to come and go.
Several years ago many swallows were hitting the windows of nearby buildings and a walkway, but the number of window strikes has dropped significantly thanks to large banners hung from windows when swallows are present.
The roosting site seems secure enough for the birds. Rink is very concerned about the possibility of the invasive emerald ash borer eventually reaching Nebraska and crippling or killing bird ash trees. To date, the insect has been detected in eastern Iowa and the Kansas City, Missouri area.
Of course, Omaha isn’t the only place to see a massive martin roost. Louise Chambers of the Purple Martin Conservation Association says you can find lodges in:
• Houston, Dallas and Austin, TX
• Richmond, Virginia
• Lake Pontchartrain, New Orleans, Louisiana
•Presque Isle State Park, Erie, Pennsylvania
• Tulsa and Oklahoma City, Oklahoma
• Wichita, Kansas (still active but disrupted by tree trimming)
• Township of Maurice River, New Jersey
• Mann’s Harbour, North Carolina
• Portage Lakes near Akron, Ohio
This is not a complete list, of course; you can find more roost sites through the PMCA’s Martin Roost Project, an effort to document roost sites throughout the bird’s range. Late summer swallows are exciting natural sights. I strongly encourage you to visit one! — Matt Mendenhall, Editor
Watch for our December issue
Pete Dunne writes about the Purple Martin colony in his hometown of Mauricetown, New Jersey.