Many people are aware of Harriet Tubman's work on the Underground Railroad and as a scout, spy, guerrilla soldier, and nurse for the Union Army during the Civil War. Fewer know of her prowess as a naturalist.

At the Harriet Tubman Underground Railroad State Park in Church Creek, Maryland, Ranger Angela Crenshaw calls Tubman “the ultimate outdoors woman.” She even used bird calls to help guide her charges, eventually helping some 70 people, including her parents and four brothers, escape slavery.

"We know that she used the call of an owl to alert refugees and her freedom seekers that it was OK, or not OK, to come out of hiding and continue their journey,” Crenshaw says. “It would have been the Barred Owl, or as it is sometimes called, a 'hoot-owl.' 'They make a sound that some people think sounds like ‘who cooks for you? Who cooks for you?’ ”

That nugget comes to Crenshaw from the park’s historian, Kate Clifford Larson, author of the Tubman biography Bound for the Promised Land. “If you used the sound of an owl, it would blend in with the normal sounds you would hear at night. It wouldn’t create any suspicion,” Crenshaw says.

Tubman made 13 trips back to Maryland between 1850 and 1860 to guide people to freedom.

Harriet Tubman spent much of her young life in close contact with the natural world. Likely born in 1822, she grew up in an area full of wetlands, swamps, and upland forests, giving her the skills she used expertly in her own quest for freedom in 1849. Her parents were enslaved, and Tubman’s owners rented her out to neighbors as a domestic servant as early as age five. At seven, she was hired out again, and her duties included walking into wet marshes to check muskrat traps. Tubman also worked as a field hand, in timber fields with her father and brothers on the north side of the Blackwater River, and at wharves in the area. All of this helped when, later, Tubman made 13 trips back to Maryland between 1850 and 1860 to guide people to freedom. The abolitionist William Lloyd Garrison dubbed Tubman “Moses.”

“It was in those timber fields where she learned the skills necessary to be a successful conductor on the Underground Railroad,” Crenshaw explains, “including how to read the landscape, how to be comfortable in the woods, how to navigate and use the sounds that were natural in Dorchester County at the time.”

Being able to travel and navigate was paramount for people risking their lives for freedom, and that's why it helped that Tubman was an astronomer, too, says Eola Dance, former coordinator for the National Park Service’s Network to Freedom program. Like other freedom seekers, Tubman used the North Star and the Big Dipper to orient herself.

“Tubman was leading family members as well as strangers from Maryland to Philadelphia, New York and as far as St. Catharine’s, Canada, by traveling at night, using science to find her way," Dance says.

Botany proved another necessary skill; people used plants for food and other survival needs. “Whether it was using certain plant life to quiet babies, or it could be relieving pain or cleaning wounds, this was the type of knowledge that Tubman had,” Dance says. Travelers along the Underground Railroad would have also looked for vegetables such as okra, tomatoes, collard greens, and trapped animals, such as muskrats, she notes.

Tubman’s natural expertise also helped her after her Underground Railroad days when she served in the Union Army, says Dance. She arrived at Fort Monroe, in Hampton Roads, Virginia, in 1861. Her experience with the waterways she crossed repeatedly while shepherding freedom seekers was essential again.

“If you’re thinking of traveling from Maryland through Pennsylvania, Tubman would have had to cross several rivers, creeks, and streams, and that would have been important not only directionally, but also something we don’t talk about as much: as in the way people were tracked,” Dance says. “Freedom seekers would have been tracked by dogs, and by traveling through the water and knowing these waterways, it would have aided them in throwing off their scent so that the dogs would not be able to find them.”

At the Harriet Tubman Underground Railroad State Park, Crenshaw likes to memorialize Tubman's connection to birds through verse. She’s memorized former U.S. poet laureate Robert Hayden’s poem Runagate, Runagate, which mentions Tubman, and also the owls she mimicked with such accuracy.

Hoot-owl calling in the ghosted air,

Five times calling to the hants in the air,

Shadow of a face in the scary leaves,

Shadow of a voice in the talking leaves.

Combined, Harriet Tubman’s understanding of the human environment, surrounding landscapes, and wildlife prepared her for both the great and small tasks of the Underground Railroad and the Civil War. To Dance, what's incredible is that Tubman began acquiring her expertise as a child, while doing what she had to do to just survive. “We don’t really think about what knowledge and skills she had to have,” Dance says, “in order to accomplish the impossible.”