Beach bird nesters have bad year, sea turtles faring well

Peter Vankevich

The downward spiral in the spring nesting season on Ocracoke began when a sustained low-pressure windstorm in early May brought overwash along the beach for several days and especially at South Point.

Flooding destroyed nests of the Common, Gull-billed and Least Terns. 

After the storm system receded, nesting resumed, but by late May, the mixed colony, that also included Black Skimmers, failed leaving one Least Tern colony. The failure was likely due to a combination of heavy rain, high winds and mammalian predation, according to Amy Thompson, Ocracoke’s lead biotechnician for the Cape Hatteras National Seashore.

On South Point, Least Terns were the only successful colonial waterbird; fledgling counts topped out at 96.

By comparison, in 2021 on South Point, there were an estimated total of 525 nests: 253 Least Terns, 20 Black Skimmers, 38 Common Terns and 14 Gull-billed Tern nests. The number of fledglings is not available.

There was initial good news up at the north end of the island as Least Terns and Black Skimmers started nesting, the first time in years.

The site of the colony of Least Terns was a bit dicey as they took to the beach in the narrowest part of the island where the sandbags along NC 12 are located.

This is a vulnerable area since even if a tropical storm or hurricane is several hundred miles out in the Atlantic the swells from it can reach the Outer Banks and wipe out the nests and hatchlings.

Black Skimmers nested on the sandy raised area of the bulkhead next to the South Dock ferry terminal. At one point, NPS counted about 35 nests.

Unfortunately, these nests failed as well, not due to weather, but to mammalian predation.

“Through use of our trail cameras, which we had installed at both of these colonies, we were able to determine that domestic cats and opossums made frequent visits to the Black Skimmer colony on the ferry dock bulkhead and to the Least Tern colony on the sandbag dunes,” Thompson said.

American Oystercatchers on Ocracoke didn’t fare any better.

Some of the oystercatcher nests were lost to overwash during the May storm, but the prolonged high winds caused nest abandonment as it became life-threatening for the adults to stay with the nest.

Thompson said that in some cases, the effort to keep the nests from filling in with sand and the eggs from getting buried became too energy demanding.

“We have camera footage of one oystercatcher pair, that had a nest located just south of the sandbag dunes, attempting to unbury their eggs on several occasions,” she said. “Eventually, that nest was abandoned. This specific pair did indeed end up re-nesting on top of the sandbag dunes on May 23 and raised two chicks that successfully fledged.”

Two other oystercatcher hatchlings this season were believed to be victims of ghost crabs.

Of the 16 nest attempts on Ocracoke, only two fledglings survived. Last year there were 14 American Oystercatcher nests that produced nine fledglings.

To brighten this story, nesting sea turtles are having another great year with the second highest number of nests from the record of 147 in 2019.

By Aug. 28, there were 113 nests, up from 97 last year. All are loggerhead nests except for five green turtles.

Thompson was pleased to say this season had the highest number of nest-sitting volunteers. “They have been a huge help this hatching season,” she said. “Ghost crabs are a prevalent predator to sea turtle hatchlings and our volunteers have been able to provide assistance to the hatchlings allowing them to reach the water safely.”

A full nesting report won’t be available until fall as some sea turtles show up to nest as late as August, and the average incubation period is 60 days.