John Latimer is waiting for the monarch butterflies.

They are a marker of late spring for the 60-year-old Minnesota mail carrier, who travels 100 miles each day on rural roads near Grand Rapids, Minn. Over the last 25 years, in between delivering letters and packages, Latimer has recorded a bounty of data on the changing seasons along his route, from the blooming of yellow lady's slipper each spring to the onset of lake ice in the winter.

This year, by his calculations, spring is coming a week late.

"The lilac bloom used to be around the first of June. Then, for a long stretch, they began to bloom on May 25 or 24 or 23. One year it was as early as May 20th," Latimer said, drawing on almost 15 years of computerized records. "This year, it was June 4."

Latimer's hobby is not just a way to pass the time as he delivers mail. He is one of an emerging breed of "citizen scientists" whose observations of nature help professional researchers better understand how climate change is shifting seasonal events like spring blooms, winter ice, and bird and animal migrations.

"Citizen science projects really seem to be popping up like crazy," said Greg Butcher, director of the Audubon Society's Christmas Bird Count. At 110 years and counting, it is thought to be the oldest volunteer science effort in the United States.

Newer efforts include projects that ask the public to record the timing of lake freezes and thaws, juniper blooms in the southwestern United States and honey production in beehives across the country.

The federal government has also gotten into the act, through the National Phenology Network it is organizing with the help of universities, conservation and environmental groups, and state agencies.

'Shocked' by what the bees knew

"About five years ago, the United States started organizing to understand how climate change would affect ecological systems," said Jake Weltzin, the U.S. Geological Survey scientist now serving as the network's interim director. "It became clear that to really get a handle on what was going on across the entire continent, you'd need lots of observations."

That is where volunteers come in, especially since many seasonal changes are easy to track. While the approach sounds simple, some older projects have yielded surprising -- and scientifically sound -- results. An analysis of 50 years of data on lilac blooms, for example, showed that earlier flowers signal warmer, drier years with above-average summer wildfire seasons.

In southern Maryland, amateur beekeeper Wayne Esaias compared 15 years of detailed, daily observations of honey production in his hives and found the bees' output began earlier each year, as spring came earlier. Esaias, an oceanographer at NASA's Goddard Space Flight Center, then compared his bee data to satellite images that showed trees and plants' greening was also happening earlier -- and in lockstep with the start of honey production.

"I was shocked," Esaias said. "My nectar flows have changed by almost a month, and we really didn't appreciate it. That's associated with about a 3-degree Fahrenheit increase in cold winter temperatures. It kind of sneaks up on you."

With support from NASA, Esaias has recruited 73 other beekeepers to monitor their honey output by placing an old-fashioned scale under each hive, then taking daily measurements of the hive's weight and the weight of any honey the beekeeper removes.

Tweeting the arrival of spring

Technology is at the core of the new citizen-science movement. Facebook, Flickr and Twitter are among the Web tools that organizers lean on to help recruit new volunteers and keep old hands coming back for more.

"The Internet," said Weltzin, "is the great flattener."

Project BudBurst's volunteers can log their observations using a Web form -- and then instantly see their contributions added to a Google map dotted with other reports from points across the United States.

"It's instant feedback," said Paul Alaback, the project's lead scientist. "It reinforces the idea that these observations that people are making are valuable and available. It's not going into a shoebox somewhere."

Latimer, the Minnesota mailman, uses Twitter to record shifting seasons along his rural delivery route -- and connect with listeners of his public radio show, KAXE's "Phenology Report."

"The apple and crabapple trees are absolutely at their peak of bloom," he wrote May 28. "Great torches of magenta and white, they stand uplifted and uplifting."

It is a far cry from the meticulous records of bird sightings logged on index cards by generations of birders across the United States. Their painstaking observations, collected between the 1880s and 1970, are now stored at a U.S. Geological Survey research center in southern Maryland.

The agency is now scanning the cards and recruiting volunteers to transcribe the decades of data they hold into a modern computer database, but it is slow going.

"They have 6 million cards," said Weltzin, the National Phenology Network scientist. "They had so many people participate for so many years, it's very difficult to save those data."

Meshing backyard observations with longer-term records

For many of the new citizen science programs that deal with climate change, an element of consciousness-raising is built in.

"Climate change is hard to get a firm grasp on," said Alaback, Project BudBurst's science director. "People have images of polar bears and ice caps, but the idea that it's happening in their yards is a pretty powerful way to get them thinking more about the issue."

But organizers say they are equally interested in collecting high-quality data that working scientists can use in peer-reviewed, published studies.

With observations stretching back more than 100 years, the Christmas Bird Count records have been used in more than 200 published analyses, Butcher said, including a recent Interior Department report that used 40 years of records to document a decline in a third of the United States' 800 bird species.

The Audubon count's leaders also are trying new approaches to help them monitor the effects of climate change. They hope to develop standard routes or positions for birders to monitor, to build a portrait of the changing environment at each station.

"Right now, it's less standardized than you'd want it to be for the kinds of uses we're putting [the observations] to," said Butcher.

At the other end of the spectrum, with just two years of data in hand, Project BudBurst scientists are trying to link their work with older records. Alaback, who collected phenology data in coastal Alaska in the 1980s, said BudBurst volunteers are now reporting from some of the same sites. He hopes that connecting the old with the new will allow them to quickly leverage the fledgling BudBurst data set into useful scientific analyses.

Organizers at the National Phenology Network are developing an array of strategies to hone the quality of their new data, ranging from an iPhone application -- still in development -- to help identify plants, to safeguards built into Web reporting systems.

See something strange? Get out your iPhone

"If someone goes to enter a red maple into our system, but they're in Tucson, we'd like our database to say, 'Guess what? You're outside the range,'" Weltzin said. "Ideally, we'd then ask them to send in a picture."

In the end, enticing "citizen scientists" to keep reporting may be the toughest challenge for program organizers.

The Maryland Science Center in Baltimore has just launched a program to track the bloom of the black-eyed Susan, Maryland's state flower. With support from a National Science Foundation grant, the center is distributing seed packets at events throughout the Baltimore area, hoping to recruit volunteers to plant and monitor the bright yellow blooms. But just four prospective volunteers showed up at a recent training event, said Katie Stofer, director of the museum's C3: Communicating Climate Change program.

"The training wasn't necessary to participate. It was more, 'If you want to come ...,'" she said. "We weren't really discouraged with that number."

But since black-eyed Susans bloom in summer, when school is out, that cuts out participation by the elementary, middle and high school science classes that are one of the science center's core audiences.

Melinda Hughes-Wert, president of Nature Abounds, said she is setting realistic goals for her group's new IceWatch program, which asks volunteers to report observations of lake and stream freezes and thaws.

"We want them to do it regularly, once a week -- but if they can't, we understand," Hughes-Wert said. "We're giving our volunteers reference guidelines, but we're not hammering them with too many specifics.

"Right now, our goal is simple," she said. "Whet the whistle, and get them going outside."

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