Citizen scientists

Every night, legions of amateurs rove the sky for comets and supernovas; every morning they walk neighborhoods and beaches to assess the damage from the latest storm, or keep detailed records of weather or the habits of local birds.

In neighborhoods across the country, a growing number of ordinary people are taking up side careers in science.

Wielding salinity meters and sterile flasks, speaking in scientific names, and keeping a sharp eye on their birdfeeders, the latest worker bees in scientific research are as likely to have taught high school history as worn a white lab coat.

''More and more organizations are realizing the power of the citizen scientists and this incredible research they've got [going on] in their own backyard," said Shawn Carlson, executive director of the Society for Amateur Scientists, a group that lobbies on behalf of the backyard tinkerer.

Such citizen scientists follow in a grand American tradition: amateur scientists Ben Franklin and Thomas Jefferson founded democracy while fiddling with electricity and experimenting with new agricultural technology. Today's global warming predictions depend in part on weather observations telegraphed by hobbyist scientists to the Smithsonian Institute in the 1800s. Amateur ornithologists collected the bird eggs that helped biologist and writer Rachel Carson to understand that DDT was building up in the food chain and interfering with bird reproduction -- work made famous in her 1962 book, ''Silent Spring."

But over the past decade, ''citizen science" has blossomed, particularly in the area of environmental monitoring.

Eric Hutchins, a fisheries biologist for the NOAA Restoration Center, which awards grants to citizen-based wetlands restoration programs, said the community-based program, for example, has ballooned from a budget of $250,000 nine years ago to $14 million today.

Earthwatch, a nonprofit group in Maynard founded in 1971, with 39 volunteers and four projects, last year sent 4,224 volunteers to do science around the world, from paleontology, to tracking manatees in Belize.

Cornell University's FeederWatch program, has grown since 1987 from a few thousand random bird watchers across the country to a well-organized group of 16,000 people who identify and count birds, sending in data that appears in prestigious scientific journals.

''Initially, there was an awful lot of resistance to it in the scientific community, because there's this idea that volunteers can't collect data, you have to go through all the schooling," said David Bonter, project leader for FeederWatch.

But now scientists in many fields depend on trained citizen groups to -- for instance -- tag monarch butterflies, migrating from the East Coast to Mexico each year, and to call to frogs in the dead of night, counting and weighing the ones they catch. Some citizen scientists are even getting published.

This newfound enthusiasm has been triggered by many factors, from retirees' nostalgia for less developed times, to a sense that even a small group of people can make a difference.

The Internet, which has expanded networks of community scientists and the ability to share data, has also had a huge impact. And now, the technologies that ordinary people have in their homes -- computers, telescopes, and global positioning systems -- rival the equipment used by scientists working in the field.

As population growth continues to fuel development , issues like habitat loss, invasive species, and erosion literally appear in people's backyards, making neighbors into scientific stakeholders. And scientific questions outstrip the people power and resources of even the best-funded federal and local programs.

Nonprofit groups, scientists, and government agencies have begun to spend a few hours training amateurs to record data in a systematic way and allowing them to submit their findings over the Internet.

''All they've got to do is take people's native interest in a subject and form a program that integrates their skills and talents into a larger picture," Carlson said.

At Cold Storage Beach in East Dennis, a dozen members of the Quivet Neck Homeowners Association trekked out onto the beach late this summer to measure tiny changes in the elevations of the dunes and the position of the low tide lines. The group had been taking data for only a few years, but many had been citizen-scientists for much longer, walking the beach and making hypotheses about how dredging, new erosion controls, and storms took their toll over decades.

''I live in a house that overlooks the beach. I used to be able to see the beach from the second floor, but now it's blocked," said David Miller, 76, a retired geologist who worked with a team of neighbors, inching slowly from the dunes toward the shore. The group used a pair of striped rods and simple geometry to create a beach profile for Jim O'Connell, a coastal processes geologist from Woods Hole Oceanographic Institution who analyzes the data.

''The difference is, Jim's not just doing this here. He can tell us how the changes he sees in our backyard" link up to changes in other places around the state, said Jeanne Linxweiler, a former schoolteacher who has been walking the beach for 65 years.

O'Connell said that while occasionally a professor and a graduate student will spend a semester examining the beach, a more comprehensive picture of the life of a beach was emerging from citizen-gathered data.

For instance, while geologists have long known that beaches shrink in winter and grow in summer as sand washes on and off shore, a group of volunteers at Rexhame Beach in Marshfield collected data over the past six years indicating the shoreline shifted, on average, 50 feet between seasons. In a report O'Connell presented at a scientific conference in Louisiana this summer, he noted that the citizen data provided clear evidence that estimates of shoreline change, often taken from aerial photographs, are error-prone.

''This has never been done before. . . . It's totally cost-prohibitive to get surveyors" to do this work, said O'Connell, who now has a team of 70 watchers at 11 area beaches.

It's not just about the data, though. Whether they're backyard astronomers, vacation fossil hunters, or environmentalists, after the study is published and grant money is spent, these amateurs keep coming back, with an even stronger sense of stewardship.

''This afternoon, we're going out at 5 p.m. to do a salinity test," said Bob Birtz of Bourne, who for eight years of his retirement has been working to restore Wings Neck Salt Marsh, which lies within sight of his backyard. ''I feel like it's my baby."

Carolyn Y. Johnson can be reached at cjohnson@globe.com.