Conceived in 1900 as an alternative to shooting birds, CBCs are now in their 116th year and have spread to the four corners of the U.S. and beyond, with surveys held in such far flung locales as Brazil and Guam. Last year, over 72,000 people participated at 2,462 locations — most of them in the U.S.

Many of the surveys, such as Winston-Salem’s, are sponsored by Audubon chapters. Each location is a circle with a diameter of 15 miles. Our area is centered at I-40 and Silas Creek Parkway and covers most of Forsyth County.

A date to conduct the count is selected within the period from 11 days before Christmas until 11 days after, or Dec. 14 to Jan. 5.

Organizers recruit participants to cover the circle by walking and driving. Some folks are out before sunrise or after sunset in order to listen for owls, but most start around sunrise and continue until afternoon or dusk.

The team’s goal is to identify every bird they see or hear and tally how many they find of each species.

We typically field 45 to 55 people in 12 teams. These teams count thousands of birds of 85 species or more.

The motivation for most participants is the chance to see one of the rarer birds that shows up in winter, such as two rufous hummingbirds that appeared at a Buena Vista residence last year — birds far from their normal winter range in Mexico, or a Ross’ Goose found near Bethania. For others, it’s the chance to see an unusually large number of birds typically seen in smaller numbers. Two years ago, 150 ring-necked ducks were seen at Salem Lake, and a flock of 110 cedar waxwings was found at Historic Bethabara Park.

For me, it is these things plus a little extra motivation simply to get out and enjoy nature in winter.

But the greater value of Audubon’s CBC is the massive database that is generated by thousands of volunteers each year. This data can give a clear picture of what is happening with bird populations across the country. Much of the news is daunting, but there are some bright spots.

Several bird species were in steep decline in the 1960s. The peregrine falcon was extinct in the U.S. east of the Rockies and its populations had declined by up to 50 percent west of the Rockies. It was placed on the Endangered Species List in 1973.

The brown pelican was classified as endangered in 1970, and the bald eagle in 1978. These and several other birds were affected by the broad-spectrum pesticide DDT that had built up in the prey of these species causing eggshell thinning resulting in a high incidence of breakage and embryo mortality.

With the banning of DDT in 1972, all three species started a remarkable recovery. Brown pelicans were removed from the list in 1992. By the late 1990s, the bald eagle had breeding populations in all but three states. The peregrine falcon has recovered so well that there are 10 to 12 breeding pairs in North Carolina, including a pair that has successfully nested in downtown Charlotte and another pair often seen in downtown Winston-Salem in winter.

DDT was considered an important tool by agriculture in the 1950s and ‘60s, and the battle to ban it was hard-won. But other threats to the environment and birds will be harder to defeat.

CBC data and other research show that two birds formerly quite common are now declining rapidly. Another falcon — the American kestrel — and the well-known bobwhite are both suffering from loss of habitat as urban sprawl gobbles up farmland and farming practices make remaining land unsuitable.

These are just two of many species affected by habitat loss. Most of our northwest counties are still largely rural, but much of their land is being lost to development, displacing birds and other wildlife.

While habitat loss remains a grave threat to the environment, global climate change looms as a far greater problem. Significant changes in temperature, weather patterns, sea levels, the intensity of storms and other climate factors will have profound influences on birds.

Birds evolved to thrive in the environment of the Triad and the rest of North America over many thousands of years. They can’t adapt in the short time that the new conditions that global climate change will create.

In the meantime, take joy in the birdlife around us. The Christmas Bird Count is just one of the ways in which to do that. But we will engage in this century-old practice with growing concern over the future of these creatures that share this world with us.

• Forsyth Audubon will lead its monthly bird walk on Jan. 9 at Salem Lake. Meet at 9 a.m. at the parking area on Linville Road at the east end of the lake. The walk is free of charge and open to the public.