Work begins on Outer Banks bridge known for purple martin migration

Kari Pugh, The Virginian-Pilot
·1 min read

Lane closures are in place and work is underway to preserve the Old Manns Harbor Bridge on the Outer Banks, but the project shouldn’t impact the bridge’s most notable travelers – thousands of migrating purple martins.

Formally called the William B. Umstead Bridge, the span between Roanoke Island and Manns Harbor is undergoing a $33 million bridge preservation project that will require a full closure of the bridge early next year. But for now, the N.C. Department of Transportation says motorists should expect some brief delays due to lane closures, which will be controlled by portable traffic signals.

The project, awarded to Coastal Gunite Construction of Cambridge, Maryland, involves the repair of deteriorated concrete on the footings, piles and caps of the substructure, as well as expansion joint replacements, crack sealing and deck surface treatment on the 68-year-old bridge.

The work is not expected to impact the purple martins that nest in the bridge during late July and August, as bridge work will not occur between 7 p.m. and 7 a.m. during the nesting season.​

From July to August, the west end of the bridge on Croatan Sound becomes home to more than 100,000 birds as they prepare for their annual migration to Brazil. The birds roost under the bridge at night, departing at dawn to feed and returning at sunset. The flock is so large during its peak that it can be seen on the National Weather Service’s Doppler radar.

When the birds arrive in sufficient numbers, the speed limit on the bridge drops to 20 mph at sunrise and sunset, with NCDOT activating flashing lights to alert motorists.

Purple martins have been roosting at the bridge for at least 40 years.