For three weeks, upwards of 60,000 volunteers will head outside as part of the largest, longest-running wildlife census in the world: the Audubon Christmas Bird Count.

From the Arctic Circle to New Orleans to South America, these volunteers take part in 2,000-plus "count circles" with passion and commitment; they know they belong to an army that has made a difference since 1900. They are among the millions of community heroes who act when Congress won't, who take conservation personally, and who teach their kids that individual action matters. If that all sounds pretty inspiring, it is.

From December 14 to January 5, these crowd-scientists provide the information that scientists need to understand how environmental changes are affecting birds. The data they gather help land use planners avoid disturbing precious breeding grounds. Just three months ago, the two major Eastern power grid coalitions agreed to factor this data in as decisions are made about where to put new mega-power lines.