Sivitz will speak on the expedition at 2 p.m. next Sunday at Pennsylvania State University's Abington campus. His program will emphasize the expedition's ties to Philadelphia, where Lewis began preparations for the trip and the pair's copious journals were first published.
Sivitz, 38, has written Discovering the Birds and Mammals of the Lewis & Clark Trail, a book he self-published earlier this year. He also teaches continuing education courses in the subject at Montgomery County Community College and Arcadia University.
His interest in Lewis and Clark dates to junior high school, but the real bug bit him when he traveled to Idaho in 1989 and noticed signs posted for the trail. Since then he has traveled to locations along the trail "every year except one," he said. He and his wife, Gabrielle, an illustrator and graphic designer, have also made Missoula, Mont., their summer home.
Lewis passed through Missoula on his return journey in 1806, Sivitz said. Clark took another route, and the two parties eventually hooked up again in North Dakota before heading back down the Missouri River toward St. Louis, which they reached in September 1806.
Cataloguing the wildlife along the trail was a four-year project that Sivitz began in 1997. He hoped such a guide would help people explore parts of the trail and identify its birds and animals. "Something for the average family to use," he said.
Along the trail he observed 29 kinds of mammals - deer, otters, elk, bears, coyotes, mountain goats and badgers, to name a few - and 220 species of birds, including hawks, crows, woodpeckers and bald eagles.
Missing now are grizzly bears - Lewis and Clark saw "dozens and dozens of them," Sivitz said - and buffalo, slaughtered mostly by white settlers. But some of the animals recorded by the explorers remain, as do many of the awe-inspiring features of the landscape.
