Skimmer, tern fledglings leave South end nests

by Kelly Corbett
Wednesday, August 14, 2013

Lumina News file photo 

An adult least tern brings a fish to least tern chicks at the south end of Wrightsville Beach on June 22, 2013.

The Wrightsville Beach south end bird colony has seen fewer nesting shore birds this season compared to 2012, but is still one of the most productive in North Carolina for black skimmers and least terns.

Some of the least terns split up this season traveling to uninhabited Lea-Hutaff Island, located between Figure Eight and Topsail islands.

Lindsay Addison, Audubon North Carolina coastal biologist, said mid-May through mid-July is the height of the bird nesting season.

Wrightsville Beach is the only developed beach posted by Audubon North Carolina. The North Carolina Wildlife Resources Commission posts other beaches.

“Compared to last year, we have fewer total birds nesting here in this colony.  Last year, we had 597 least tern pairs and we have 235 this year,” Addison said. “If it’s not the most productive, it is one of the most productive in the state in terms of producing fledglings per pair, and it has been for the past several years.”

The failure of the Masons Inlet colony on the north end coincided with the nesting birds at the south end in 2009 and 2010, Addison said.

“When they started nesting in 2011, they didn’t try at Mason Inlet at all,” she said. “They just came right here.”

On the north end, only a few least terns fledged this year. 

Hatching success rates are variable, depending on predation, storm or high tide events and disturbances.

“A 60-70 percent would be a nice success rate,” Addison said. “You can get over 80 percent in a really good year.”

During the peak count of nests on the south end, there were four oystercatcher pairs, three willet pairs, 15 common tern pairs, 137 black skimmer pairs and 235 least tern pairs.

“We go in and we count all of the nests in the colony at peak of incubation,” Addison said. “The problem when we counted the least tern nests is we had had a high tide recently and lost maybe about 30 nests.”

The nests were lost during the highest lunar tide on June 21, but most of those pairs renested. The birds that renest appear to have good hatching success, Addison said.

The hatching success numbers are not the ones with the most information, because all of the shore bird species nest up to three times if they lose their eggs.

“What you really care about is fledglings per pair, because that’s productivity, that’s how many new birds are producing each season,” Addison said. “That is also the most difficult number to get, because the chicks, obviously once they can fly, are super mobile. They don’t have to stay at the colony and it’s difficult to count them for those reasons.”

There is not a reliable fledging number for least terns, because there have been fledglings since June and they do not stay around the colony long. 

There were about 120 fledgling black skimmers, at about one fledgling per pair. Three oystercatcher pairs each fledged a chick.

After the birds choose their habitat, Audubon staff puts up postings to reduce human disturbance and ensure they are successful. The postings framing the bird colony will stay up until Aug. 31. Without those postings, the birds would not be successful, Addison said.

Marlene Eader, a first-time volunteer coordinator, marshalled 52 volunteers throughout the season. The Friday bird walks, which will continue until Sept. 13, have reached 490 people.

“Last year, we had birds roosting here at the south end beyond the end of September, so there’s still a bit to see,” Addison said.


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