The 5th of January marks the completion of the 109th Christmas bird count, a yearly rite in which groups of North American bird-lovers pick a day around the winter solstice, fan out in teams to their designated areas, and count every bird that they see.

Held every year since 1900, when the National Audubon Society proposed it as an alternative to the then-popular Yuletide activity of competitively shooting birds, the count is the longest-running volunteer science project in the world. Its data have informed reams of peer-reviewed work, such as an ongoing effort by Audubon researchers to predict how birds will adjust their ranges in response to climate change.

The count has served as a model for any number of volunteer science efforts. Such projects now flourish — not least because the Internet makes it so easy for scientists to find, recruit and coordinate the volunteers. Out in the field, examples range from Project BudBurst, in which participants report on the timing of climate-influenced botanical events such as flowering and leafing, to the Great World Wide Star Count, in which astronomy buffs check the number of stars visible in certain bright constellations as a way of monitoring light pollution.

Indoors, meanwhile, network-based projects include Folding@home, in which millions of users allow their idle home computers to be used to simulate protein folding, and Galaxy Zoo, in which participants use their prowess at pattern recognition to classify the millions of galaxies captured in telescopic images — something that still flummoxes computers.

The lesson of this list is that the world is full of enthusiastic people — and that the opportunities for researchers to tap into this enthusiasm are limited only by their own imaginations. Volunteer science is a win–win situation for all concerned. Scientists get to take on projects that would not be feasible for even the largest research group, while helping to increase the public's understanding of, and support for, science. And the volunteers get to have fun, while experiencing the satisfaction of defending the environment, fighting disease or expanding human knowledge.

So researchers should think creatively about whether the data they need, or the crunching or sorting they must do, can be outsourced to members of the public. And while they are at it, perhaps they should also consider joining one or more citizen science projects themselves. Participation in such efforts can reconnect scientists consumed with grant-writing and project management with the 'doing' of science. In the Christmas bird count, the most skilled bird spotters and identifiers are inevitably the non-scientists; professional ornithologists spend too much time doing paperwork. And, of course, volunteering for science feels good, especially when you see a black oystercatcher, say, or two merging galaxies — something fun, beautiful and rare.