By Laura & Hal Mahan
Last summer, a customer asked, “Where are all the hummingbirds this year? There seem to be way fewer than what we usually see.” Another customer comments that they are seeing lots of American Goldfinches at their feeders. “Have their numbers increased?” Have you ever wondered how bird populations are counted? How do scientists know which birds are imperiled and which might be thriving? Systematic bird surveys are one way to find out.
Starting in March, the first ever North Carolina Bird Atlas kicks off from the mountains to the coast. This five-year program is a collaboration led by the NC Wildlife Resources Commission and partner groups including NC State University, North Carolina Natural Heritage Program, Audubon North Carolina, US Fish and Wildlife Service, University of North Carolina at Wilmington and Catawba College.
This type of survey follows a few more data collecting rules than the familiar bird counts, such as the Audubon Christmas Bird Count. For the NC Bird Atlas, the state has been divided into 937 blocks that are roughly ten square miles, each with its own coordinator. Volunteers are asked to slow down and record not only the species of birds they see but the behaviors of the birds, such as singing or gathering nesting material. There is also a time requirement. The blocks are surveyed for 20 hours during breeding season and ten hours in winter, each with two nighttime visits. Data will be reported using the eBird app. Then the blocks are surveyed again using the same methods each year.
The concept of a bird atlas has a long history. In the early 1960s, US Fish and Wildlife Service biologist Chandler Robbins received a letter from a concerned mid-westerner asking if robin populations were in decline. Scores of dying birds had been observed on college campuses and main streets across the US as the pesticide DDT was in widespread use to combat mosquitoes and agricultural pests. When Robbins realized that he couldn’t really answer that question with certainty, he began to think about devising a systematic way to monitor bird populations over time.
Robbins and his advisors and volunteer testers devised a simple yet strict method of surveying birds by establishing 600 road routes in the eastern US. On each route during the peak of the breeding season, the observer visits 50 stops in sequence, and for three minutes counts all birds heard or seen. This method has been gathering data on birds since 1966 and has become the primary source for long-term data on trends in populations for more than 400 of North America’s breeding birds.
Here in North Carolina, researchers hope to use what they learn from the new NC Bird Atlas to help wildlife biologists and land managers understand current trends in bird populations. “More people than ever before are learning to identify the cardinals, chickadees and all the other bird species at their backyard feeders,” says Scott Anderson, bird conservation biologist at the NC Wildlife Resource Commission. “The NC Bird Atlas is a great opportunity for people to use these newfound skills and give a little back.”
Visit NCBirdAtlas.org for more information. Laura and Hal Mahan are owners of The Compleat Naturalist, located at 2 Brook Street in the Historic Biltmore Village. To learn more, visit CompleatNaturalist.com or call 828.274.5430.