Purple martins again are flocking to Lake Murray, delighting bird-watchers and shoreline residents for another summer.

Thousands of the birds are returning to their long-time roost on Bomb Island, relieving anxiety lingering when they went elsewhere in 2014 for unknown reasons. They returned last year, but in smaller numbers.

“The birds are back, but the population is much smaller than it was,” said Sidney Gauthreaux, director of the Radar Ornithology Laboratory at Clemson University. “It’s not really as spectacular as years past.”

No one counts, but the roost has been as large as 1 million birds at times, according to unofficial estimates. It’s one of the largest roosts of purple martins in North America.


Their numbers today are fewer, apparently due to higher mortality when the birds winter in South America and less reproduction, Gauthreaux said.

After their young leave the nest, the birds spend the summer consuming insects on trips that cover hundreds of miles before returning to their large communal roost on the island.

The roost at the lake apparently began to build sometime in the late 1980s, officials say. By 1994, researchers were estimating its numbers in the hundreds of thousands.

The spectacle has become a summer staple on the 650-mile lakefront.

Boaters sail near Bomb Island in July and August to watch the acrobatic cloud that the birds create at dawn and sunset as they depart and come back from hunting food.

It’s a phenomenon promoted by tourism officials. “Everybody is ‘Wow! I had no idea,’” said Miriam Atria, chief executive officer of the Capital City/Lake Murray Regional Tourism Board.

Tour boat operators are busy with nightly trips to view the flights despite suggestions the number of birds is down.

“Our passengers have not been disappointed,” said Ken Colton, operator of the Spirit of Lake Murray. “It is inspirational to see.”

The birds appear to roost more across the island than settling mainly on its east end facing the dam as they did before, he said.

But the cloud “is nothing like the tornado it used to be,” said Richard Peterson, chief executive officer of the Greater Lake Murray Chamber of Commerce.

Briar bushes should be added to the island to give the birds more spots to stay overnight, replacing landscape that has died out naturally, he said.

“We need to create new habitat,” Peterson said. “If we do that, the birds are going to come back in multitudes.”