Armed with binoculars, bird guides and checklists, bird-watchers will venture across Beaufort County next month on a yearly mission to make a difference and experience nature.
From Dec. 14 to Jan. 5, tens of thousands of volunteers throughout the Americas will participate in the National Audubon Society's 112th Christmas Bird Count.
Audubon and other organizations use data collected in what is billed as the longest-running wildlife census to assess the health of bird populations and guide conservation efforts, said Barry Lowes, coordinator of the Hilton Head Island Audubon Society's Dec. 14 count.
"It's a huge exercise that gives a collective snapshot of what's happening to the bird population locally, nationally and internationally," said Lowes, who has participated in the bird count since 1982. Counts have been taken on Hilton Head since 1973.
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Local trends in bird populations can indicate habitat changes or signal an environmental threat, such as groundwater contamination or poisoning from improper use of pesticides, Fripp Island Audubon Club board member Ken Scott said. The Fripp club will conduct its third bird count Dec. 17.
In 2007, the data revealed that populations of some of America's most beloved and familiar birds have taken a nosedive during the past 40 years. The data also identified 178 rarer species in the continental U.S. and 39 in Hawaii that are imperiled, according to the Audubon Society.
That is true locally, as well. The area is habitat to diverse species, but the number of even common birds has dropped dramatically, primarily because of pollutants in the ecosystems and loss of nesting areas, Scott said.
"For example, 20 years ago you would have seen maybe 1,000 sanderlings -- common birds that chase waves on the beach," he said. "Now, you go out on the beach, and you may see 20, far less than in times past."
Hilton Head Audubon has documented an average of 150 species of birds over the past decade. The total counted, however, has fluctuated year to year from 43,500 in 2001 to 26,800 the following year to 47,000 in 2006 to 33,704 last year.
There have been successes, including a resurgence in the brown pelican, osprey and bald eagle populations, which were once seriously threatened, Scott said.
The national symbol -- once nearly wiped out in the lower 48 states by pesticide poisoning -- has rebounded in South Carolina from as few as 13 breeding pairs in the 1960s to about 300 breeding pairs last winter. Nationwide, the bird has recovered so well it was removed from the federal Endangered Species List.
Count data also have been used to analyze climate change. Audubon scientists examined 40 years of bird-count data to determine nearly 60 percent of the 305 species found in North America in the winter shifted their ranges north on average by 35 miles.
The counts underline the importance of Audubon's role in protecting wildlife and encouraging environmental stewardship, Scott said.
Anyone can help. All volunteers are assigned to teams led by experienced bird-watchers who are familiar with their areas.
Families and those who can't join a team can help by sharing information about birds that visit their feeders and frequent their yards.
"It's a great way for children to learn about birds and develop an appreciation of nature," Scott said.
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