More than two dozen foals were born this year to the wild horses of Corolla, N.C., pushing the herd above its designated limits and meaning more of the animals will be available for adoption.

With about 30 foals, the herd stands at 108 animals–well above the desired population of 60 in a management plan adopted six years ago.

“I think it was just a good breeding season,” said Steve Rogers, herd manager for the Corolla Wild Horse Fund, a nonprofit group charged with taking care of the animals. “It kind of goes in cycles.”

But overpopulation leads to overgrazing, and possible damage to the maritime forest environment, especially in the Currituck National Wildlife Refuge. Refuge managers said this summer that the area already showed signs of overgrazing even with a lower population