Citizen science has been around for centuries, with lay people collecting data and making observations for scientists in a variety of fields. And, citizen scientists are contributing to discoveries as much in the 21st century as ever before.

Lab ecologist Janis Dickinson depends on citizen scientists to help her track the effects of disease, land-use change and environmental contaminants on the nesting success of birds.

"It goes back to the 18th century, with people studying birds in Finland," explains Dickinson, director of citizen science at the Cornell University Lab of Ornithology in Ithaca, N.Y. "It's a wonderful tradition in Europe, with a couple hundred years of data. It goes back pretty far in North America as well."

But the Internet has indeed made a huge impact on the volume of information Dickinson and other scientists can get their hands on, especially in the fields of ornithology and astronomy.

"So those are the two areas where citizen science has been enormously successful," continues Dickinson. "[And that's] because there is this wonderful match between this data that we want to gather, and what these hobbyists like to do. There is also a lot of altruism involved. We hear from people that they enjoy helping science, that they are interested in conservation."

With help from the National Science Foundation (NSF), Dickinson and her colleagues are using data from these volunteers on several research projects.

Dickinson is on the faculty of Cornell's Department of Natural Resources. Among their projects: research on the effects of mercury on wood thrushes and research on a new disease in house finches.

The input from across North America is now especially important in the study of climate change.

"For all kinds of environmental change, we are fast becoming aware that we need to be looking at these problems at very large geographic scales," says Dickinson. "And the only way to do that is with citizen science. So we absolutely have to have these monitoring schemes in place if we want to project what might be happening with climate change on birds, and even look at the effects that climate change has already had on birds."

Bird records, from the 1950s to the present

Biologist Caren Cooper combines citizen science from several decades for her work. She pulls out some weathered, yellowed file cards from a room at the lab that contains hundreds of thousands of bits of information on just about every species of bird in North America. Birdwatchers started sharing their finds in the 1950s.

"It could seem like paper would be obsolete in today's world," notes Cooper. "But these paper records are invaluable because each one is a little diary of a nesting attempt. And [as for] the birds that we see today, these are nesting records of their great, great, great, great grandmothers!"

"We have historic temperature records, too, for historic patterns on climate, in all of these different regions," she explains. "And so, we can look at what the relationships were in the past between local weather or climate trends, and the timing of when birds breed."

Laura Burkholder's job at the lab gives her some time to explore the beauty of Sapsucker Woods, which surrounds the research facility. "What's really amazing to me is, when I come out here to walk, I always see something interesting or something new," says Burkholder, who is the leader of NestWatch, a nest-monitoring project.

"There are a lot of wetlands, and birds, everything from warblers to sparrows to geese and other waterfowl. And we have many nesting birds, including some great blue herons that are nesting right over the pond," she says.

NestWatch was developed by Cornell, in collaboration with the Smithsonian Migratory Bird Center, and is funded by NSF.

Sometimes, NestWatch will get 20-30 e-mails a day from volunteers who are watching birds build nests, lay eggs, and feed their young. "They really care about the birds and they love watching them," says Burkholder. "They like seeing the nestlings and the eggs, and they are really, really careful not to impact those birds or disturb their nesting."

Before they can participate, volunteers have to learn about observing nests and birds without interfering. They must pass a quiz to get certified for monitoring, and follow a code of conduct. The tools are simple — a mirror, data sheet and pencil.

Once the volunteers log on to the NestWatch site, they can submit their findings: details like where the nest is located, what species of bird has moved in, how many eggs, how many chicks, when they leave the nest.

And, since the oil blowout disaster in the Gulf of Mexico in April 2010, NestWatch is seeking data for backyard birds that may use the Gulf during their annual cycle.

Working with school groups

The lab also works with many school groups. One collaboration with a local science center is a program called "Communicating Climate Change," or "C3."

"The kids in some of these programs will actually build nest boxes, put them up and monitor them," says Burkholder. "And not only that, they will learn about the birds that are using them, they will have target species, and they just show so much enthusiasm. They become so knowledgeable about birds. And they spread that information around. They tell their parents, they tell their friends."

Middle-school student Sophia Shi says she loves getting outdoors. "What I find really fascinating about birds is their diversity. That they all fit into one group but they all have these different characteristics," she adds.

Thirteen-year-old Jean Sinon is also intrigued by the differences in bird species. "I used to live in Africa and we have different kinds of birds and I compare them to birds here. I saw a lot of cardinals around my apartment this year. We saw fledglings and it's really cool," he says.

Owen Zhang, also 13, combines a love of photography with a growing interest in birds. "I like taking pictures of nature, mainly common birds like chickadees and robins and eastern bluebirds and swallows. I just like seeing stuff that people usually don't see, like nests, and getting the opportunity to see young fledglings," he says.

Burkholder also directs another computer-based, citizen-science project called CamClickr. It's a crowdsourcing effort that helps catalog millions of bird photos. "We need help from volunteers, to sort and tag the behaviors so that researchers are better able to look at them and to examine the nest and ask questions like, 'How often do the parents feed?' 'Does the male parent feed more often than the female, as the nestlings grow?'" she explains.

NestWatch data can be viewed, downloaded and explored by anyone interested in birds and their habitats.

This story was originally written for Science Nation and was republished with permission here. Video: Science NationMiles O'Brien/Science Nation Correspondent, Marsha Walton/Science Nation Producer.