Annual Audubon Christmas Bird Count.

• Position: Bird Watching

The longest-running citizen science survey in the world, the Audubon Christmas Bird Count (CBC), will take place Dec. 14-Jan. 5, 2014. Tens of thousands of volunteers throughout North America will brave winter weather to add a new layer to data that has shaped conservation and Congressional decisions for more than a century.

Each year, the Audubon Christmas Bird Count mobilizes over 70,000 volunteers in 2,300-plus locations across the Western Hemisphere, from above the Arctic Circle to Brooklyn, N.Y., and Los Angeles, Calif., to Tierra del Fuego. CBC tracks the health of bird populations at a scale that professional scientists never could accomplish alone.

"Audubon was a social network before the world ever heard the term," points out David Yarnold, president and CEO.

Last year's count shattered records: 2,369 counts and 71,531 people tallied more than 60,000,000 birds of 2,296 different species. Counts took place in all 50 states, every Canadian province, and over 100 count circles in Latin America, the Caribbean, and the Pacific Islands. Three new counts were welcomed in Cuba, where, for the first time, the tiniest bird in the world, the Bee Hummingbird, was included in the results.

Several interesting avian incursions were recorded during last year's CBC, including those of Northern Shrikes, Snowy Owls, and Winter Finches. The most significant event was an unprecedented movement of Razorbills (a Puffin relative) in huge numbers far south of their normal range off the...