Like Thoreau, I hike daily through the forests and fields surrounding my home. I glimpse fox, bear and coyote searching for food, and in the sky I often spy nighthawks or monarchs in their cyclical migrations.

In winter, I taste icicles dripping off cedar boughs, and in summer, I yell curses at the snapping turtles invading my pond. I know the hummingbirds arrive from their miraculous journey across the Gulf of Mexico to my home sometime in mid-April. But I've never recorded the exact date of their appearance at my feeders.

I believe Thoreau would have recorded such a monumental date in his handwritten dairies. He kept detailed observations of the natural world around his hometown of Concord, MA, from 1852-1858, and he probably would have recorded the slightest seasonal changes in the appearance of newborn rabbits or flowering bluebells.

Today, scientists are asking us to take time as Thoreau did to get outside our comfortable thermostat-driven temperatures and document changes we see in our environment. They want us to participate in Project BudBurst, A National Phenology Network Field Campaign for Citizen Scientists. The project simply asks U.S. citizen-

scientists to spend a bit of time outdoors and then enter their observations on the BudBurst website.

The more volunteers the better, for that increases the database and lessens the chance of errors. The database of observations will allow scientists to investigate climate change.

Citizen-scientists can monitor almost 4,000 plants through Project BudBurst, but the program specifically targets 100 plant species that are easily identified and found across the United States, including common dandelion, yarrow and elderberry. Everyday sightings of when such plants bloom offer scientists a broad vision of how our nation wakes up in springtime.

By comparing current observations to ones from years ago, they can answer questions. Are cherry trees blossoming sooner? Is ragweed releasing pollen earlier? What other changes might be brought on by global climate change? How do these changes affect animal populations?

Anyone from children to senior citizens can participate, and many of these plants under study are found in backyards and school grounds. In fact, school groups and science classes are strongly invited to join Project Budburst.

Dr. Kay Havens, director of plant science and conservation at the Chicago Botanical Garden, encourages children to become phenologists. "You can sign in and become a Budburst member and record your location. And after that you can look at species guides, decide which species you want to monitor, watch them in your own yard and then log in and tell us the day that they first come into bloom, or you see the first leaf or you see the first fruit."

Phenology is, as Kirsten de Beurs, a geography professor at Virginia Tech, puts it, "the study of periodic biological events," Scientists in this field investigate how non-living factors of our environment such as day length or temperature affect living species and their habits such as migration or blossoming.

Through the years, farmers have used such information to increase crop production, and I personally know when to avoid the ragweed-filled fields in the fall. When the ironweed by Big Branch begins to bloom in its purple glory, my sneezing and drippy nose soon follow.

By documenting and evaluating even the smallest personal phenological events, we can further understand larger changes in our surroundings.

Findings are already being tallied. For example, from Thoreau's time in 1852 to ours in 2006, scientists have found that Concord warmed by 2.4 degrees C.

"On average, plants in Concord appear to flower now seven days earlier than they did when Thoreau made his observations," report state scientists A.J. Miller Rushing and R.B. Primack. They continue, "Most of this change in flowering time is probably due to rising winter and spring temperatures." These rising trends in temperature have been documented worldwide, and they are affecting the flora and fauna around my home too.

This year I will record the exact date that I spy the first hummingbird quenching its thirst at my feeder. I also plan to document for Project Budburst the blooming of monarda and lobelia, two flowers that hummers love. I think Thoreau would be pleased.

For information, visit: www.windows.ucar.edu/citizen_science/budburst/index.html