In a “Big Year,” a birder chooses a geographical location, then tries to see as many species as possible during a calendar year. A variation on the concept is a Big Green Big Year, or BIGBY–seeing as many species as possible without using any fossil fuels.

Local birders Andy Dettling, Jacco Gelderloos, and Laurent Fournier are all doing a BIGBY in 2011. It’s a little competitive–each has easy access to different habitats–but they’re also planning to ride some of their longest bike trips together. (Gelderloos and Fournier are confining their search to Washtenaw County; Dettling is covering Wayne County as well.) After spotting 164 species in 2010, Gelderloos is hoping for 175 or even 200 this year. By mid-April he’d already seen 103 in Washtenaw County, while Dettling and Fournier have a little catching up to do, with seventy-seven and sixty-six species respectively in the county.

The main motive for a BIGBY is environmental, because pursuing rare bird sightings by car contributes to global warming–and so, distantly and ironically, harms the birds’ habitats. But there are other benefits. It’s great exercise, with six-to-eight-mile runs and fifty-to-100-mile bike rides. On their longest ride last spring, Gelderloos and Fournier logged an amazing 114 species.

For the participants, green birding is a way to be closer to nature, to see and hear birds more vividly. “You hear and see more if there is no engine noise or a window to keep you from experiencing the outside world,” Gelderloos says. In February, Dettling set off before dawn, “in the snow, into the wind, on a mountain bike, in my heavy hiking boots, with snow pants on, while carrying a scope in a backpack.” Seeing a short-eared owl lit up by early morning sun made it worth it.

Although BIGBY trips can be Herculean, it’s possible to do green birding without taking on such a physical challenge. There are 124 species that breed in Ann Arbor’s parks and natural areas. Nichols Arboretum is the best-known birding spot, but many others can easily be reached by foot or bicycle.

Check out Bird Hills Nature Area, off Huron River Drive, to hear wrens and look for brilliant orioles and yellow warblers. Or visit the wetlands at Mary Beth Doyle Park on Packard to see wading great blue herons and shorebirds like killdeer.