How an Artificial Island Led to the Rebound of a Declining Waterbird in Maryland

In the coastal bays of Ocean City, Maryland, a floating wooden raft has become a thriving nesting colony for hundreds of sleek, silver-grey Common Terns – a remarkable conservation success story helping to restore one of Maryland’s most threatened coastal birds.  

During the 2026 breeding season, biologists documented hundreds of Common Tern nests across two coastal colonies: 376 on the raft and 84 at the recently restored Reedy Island, for a total of 460 nests.  

This is the strongest coastal breeding population Maryland has seen in decades and an exponential increase since the species dwindled to just 30 nesting pairs in the coastal bays five years ago. This year’s numbers represent the recovery of nearly one-third of the region's historic population. 

The rebound is due to the hard-working team of biologists from the Maryland Department of Natural Resource’s (DNR) Wildlife and Heritage Service and the Maryland Coastal Bays Program that manages the raft colony and first installed it in 2020, with support from Audubon Mid-Atlantic. 

“We have recovered the coastal Common Tern breeding population in Maryland to where we were back in the early 2000s,” said Dave Brinker, Avian Conservation Ecologist at DNR’s Natural Heritage Program. “The problem has been a lack of nesting habitat, and we are restoring that for the birds.”  

For generations, Maryland’s coastal islands provided ideal nesting habitat for Common Terns and countless other species. But decades of erosion, intensifying storms, and human disturbance have taken a toll on these fragile habitats. Historically, the Common Tern’s population reflects that decline in habitat.  

Over several decades, Maryland’s Common Tern population declined as much as 95%. In the late 1980s and early 1990s, more than 1,200 nests were recorded in Maryland's Coastal Bays. By 2020, fewer than 30 nests remained, raising concerns that the species could disappear from Maryland’s coast. 

That year, DNR, the Maryland Coastal Bays Program, and Audubon responded by launching a floating raft that mimics the natural nesting habitat terns need, while also protecting them from flooding and predation. In the raft’s first season, 23 nests produced 22 chicks. In the years since, many of the same birds have returned - demonstrating the species’ strong site fidelity, or an animal’s tendency to return to a particular area.  

“Give them a plot of land and they’ll use it,” said Kim Abplanalp, Bird Habitat Coordinator at the Maryland Coastal Bays Program. “Terns are highly social, they want to be where the numbers are. On the raft they’re offered protection in large groups and more resources to raise their young.” 

The project has grown beyond the raft itself. Habitat restoration at Reedy Beach and West Reedy Island, two small islands in the Isle of Wight Bay in Ocean City, have created a second natural nesting colony where researchers have documented birds who hatched on the raft establishing nests on the island. 

The raft also connects Maryland to bird conservation efforts across the hemisphere. Terns banded by Abplanalp and her team have been resighted during the winter in places like Punta Rasa, Argentina. 

Still, the raft is not a permanent solution for natural habitat.  The long-term goal is to restore the sand islands in the Coastal Bays that these birds have always relied on, and there are many encouraging signs of progress. 

Six years into the project, the raft continues to support increasing numbers of tern pairs and chicks, and sightings of other species have increased. Royal Terns have nested on the platform in small numbers and just this season, species like Roseate Terns, Gull-billed Terns, and Sandwich Terns have been spotted roosting on it.  

For now, the raft offers more than just a place to nest. It offers a glimpse of what habitat recovery can look like in Maryland, and hope that the coastal ecosystems in our region can once again provide the space that Common Terns need to thrive for generations to come.