Biologists with the N.C. Wildlife Resources Commission have finished another year of waterbird surveys along the coast and have documented a record number of active wood stork colonies this year.
During the annual breeding season survey, which took place in May and June, biologists found wood storks nesting at five locations in the southeastern part of the state. North Carolina is the northern most extent of the species’ breeding range, which historically has consisted of Florida, Georgia and South Carolina.
Wood storks are large, long-legged wading birds with a bald, gray head, prominent bill and mostly white body. Found in the shallow waters of fresh or brackish swamps and wetlands, they feed primarily on fish and other aquatic invertebrates, although they also will eat crayfish, crabs, snakes, small turtles, juvenile alligators and rodents.
They are social birds that nest in a flock —a colony — with other wading birds, such as egrets and herons. While herons and egrets are common in North Carolina, wood storks are a relative newcomer to the Tar Heel state. Commission biologists found the first colony in 2005 when conducting a bald eagle survey. This year, they counted 354 nests in the five colonies, during the ground-based portion of the survey.
These colony nest sites are typically 10 to 15 feet above water, and can be as high as 80 feet, depending on location. The female builds a nest from materials the male brings to her, creating a flimsy platform of sticks, lined with twigs and leaves. Because of these precariously perched treetop nests over water, biologists can have a difficult time accurately counting nests from the ground, which they do by walking or using kayaks. To combat this issue, they also took photographs of colonies from an airplane and drone and will use these photos to provide additional estimates of the population later this year.
The drone survey, which began in 2018, is a partnership between the Commission and the Coastal and Estuarine Studies Lab at UNC-Wilmington.
With the substantial increase in nesting numbers this year, biologists speculate the boom is due to a combination of weather and strong, collaborative conservation efforts.
“The lack of rain earlier this year may have benefited the species by keeping water levels from becoming too high, and increasing available foraging areas that allowed the storks to more easily capture prey,” said Carmen Johnson, the agency’s waterbird biologist, leading the stork survey effort. “In North Carolina, the species is also thriving thanks, in part, to the commitment by private landowners, N.C. Parks, Audubon North Carolina, and the Commission to protect wood stork habitat.”
The wood stork is North America’s only native stork and, like many other wading birds, has suffered substantial declines in population due, in part, to the loss of wetlands across its range, which significantly reduced its food base of small fish. In 1984, it was federally listed as endangered under the Endangered Species Act. However, nearly three decades of conservation efforts improved North American populations to the point where the bird was downlisted to threatened in 2013. In North Carolina, the large bird is also state-listed as threatened and is classified as a Species of Greatest Conservation Need in the N.C. Wildlife Action Plan.
For more information on nongame and wildlife conservation projects in North Carolina, read the Wildlife Diversity’s Program’s Quarterly Reports.
Photo credit Annika Andersson/Contributed.