As Amtrak's Empire Builder train clatters down the tracks from St. Paul into southern Minnesota's bluff country and beyond, riders can amble up to the lounge car for a natural history lesson on the beautiful landscapes unspooling outside the windows.

Volunteer master naturalists such as David Schmidt of Inver Grove Heights hop aboard to tell passengers more about what they'll see — from bluffs topped with goat prairies to Ice Age Trails and the distinctive topography of Wisconsin's driftless area. On behalf of the National Park Service, Schmidt and his fellow volunteers can even help the youngest passengers earn Junior Ranger badges without leaving the train.

"There are plenty of opportunities," said Schmidt, one of more than 1,840 people across the state who've completed Minnesota's Master Naturalist courses offered jointly by the University of Minnesota and Department of Natural Resources.

The Minnesota Master Naturalist program was founded in 2005. Like the longer-established master gardener program, it's a way to train passionate learners who are willing to go forth and share their knowledge with the general public. In exchange for $275, budding naturalists are given 40 hours of classroom training, books and hands-on field trips (scholarships are available for those who can't afford the course fee). Each course offers in-depth schooling on Minnesota's three main biomes: southeastern Minnesota's "Big Woods and Big Rivers," southern and central Minnesota's "Prairies and Potholes," and northern Minnesota's "Northwoods and Great Lakes."

"There are always a lot of people who want to get into the classes," said Amy Rager, program director for the Master Naturalist Program through the University of Minnesota Extension Service. Classes are spread throughout the state and usually take place within their designated biomes. The exception is Anoka-Ramsey Community College, where classes are offered to cover all three biomes. But these classes are part of the college's biology curriculum with only six spots reserved for master naturalists vs. the typical 22 slots in designated master naturalist courses. This means the Anoka-Ramsey classes typically fill the fastest.

Minnesota modeled its master naturalist program after well-established ones in Florida and Texas, borrowing practices from both states but making adjustments to match the specific culture and landscapes of Minnesota. The program began modestly, with a mere 20 graduates its first year. So far in 2015, there are already four classes being offered with spaces for 22 students apiece, making the new year an ideal time to register for a course.

Into the field

Once they've completed their coursework, master naturalists are matched with volunteer opportunities according to their interests, talents and locations within the state.

"We try to help people find service that matches their skill set," Rager said.

Master naturalists might work with the Minnesota DNR to monitor the weather or water quality in local lakes. They might help with sighting loons. They might record annual bloom times for wildflowers. Or they can help track the movement of monarch butterflies for national groups like Monarch Watch.

Newer cameras that embed dates plus GPS locations into images make it easier than ever for amateur and professional photographers to help with citizen science efforts. Minnesota's master naturalists have contributed to respected databanks such as the ebird project through Cornell University and the National Audubon Society, the Encyclopedia of Life through Harvard's Museum of Comparative Zoology and the University of California's iNaturalist mobile app.

Other master naturalists join stewardship projects, often involving their families. Some have collected prairie seeds for regional restoration projects. Some have poured a mix of mustard and water into a one-square-foot section of earth, bringing up and counting nonnative earth worms, which can damage Minnesota forests. Others have tracked or removed invasive species such as buckthorn in parks or plucked aquatic invaders from the underside of boats.

Places such as Dodge Nature Center in St. Paul rely upon master naturalist volunteers to lead hikes, tap trees for annual maple syruping efforts or to spearhead year-round interpretive programs.

The Minnesota DNR even used master naturalists to research the people buried in the pioneer cemetery at Jay Cooke State Park. The project culminated with a volunteer-written brochure on the cemetery for inquiring visitors.

Finding a niche

Schmidt was working in IT when he and his wife, Sara Klasky, started volunteering at the Minnesota Zoo about 15 years ago. Schmidt coordinated other volunteers at the zoo's Wells Fargo Family Farm, trained new recruits and helped with a variety of special events. He was intrigued when he saw an ad for the master naturalist program in his local Inver Grove Heights newspaper in 2005. So he signed up for the "Big Woods, Big Rivers" course, with hopes of expanding the nature-based education he gained through the zoo.

He later got involved with the Dodge Nature Center after work and on weekends. By 2008, he was motivated enough to study a second biome. So he commuted to Rochester for 10 weeks with his wife and a family friend for a course on the "Prairies and Potholes" biome.

These days, Schmidt's volunteer assignments traverse the Mississippi River. He primarily works on projects through the National Park Service visitor center at the Science Museum of Minnesota.

During the past year Schmidt worked at learning stations on a Mississippi riverboat as school kids explored the river's significance. He also pitched in with a long-term project to clean up and restore the historic Coldwater Spring area, located along the trail between Minnehaha Falls Park and Fort Snelling. The natural spring drew American Indians and later traders and immigrants who came for the drinking water and established Minnesota's first settlement before Fort Snelling was built in 1824.

"[Volunteering] isn't just nature. It's also cultural history," said Schmidt, who enjoys interpreting the role Minnesota's natural resources play even in its most urban areas. In the quiet area of Coldwater Spring, there might be the rumble of airplanes overhead and towering skyscrapers just upriver, but volunteers like Schmidt can help visitors imagine its beginnings as a remote campsite and the birthplace of Minnesota.

"It's really a wonderful place," he said.

Lisa Meyers McClintick is the author of "Day Trips from the Twin Cities." Find her at www.10000Likes.com.