Amid the flock of taxidermy birds at Yale’s Peabody museum, Mary “Cassie” Stoddard ’08 feels at home. She’s intimately acquainted with the Purple Martin (Progne Subis) and could tell you how its feathers evolved their deep blue sheen. She’s on friendly terms with the Indigo Bunting (Passerina Cyanea), whose advanced vision she has studied in the lab. Although she is a virtual encyclopedia of bird knowledge and a dedicated bird researcher, Stoddard approaches her feathered pals with the enthusiasm of a child discovering them for the first time.

“I think every proper five-year-old went through a phase where he or she was obsessed with some kind of animal,” Stoddard’s close friend Erin Lin wrote in an e-mail. “For most people, after a two-week stint as a child ichthyologist, we move on to the next occupation. But Cassie kept this intense, child-like enthusiasm and sense of wonderment for birds.”

Stoddard first explored bird watching with her mother, a “backyard birder” who learned about birds from her own mother. As a child, Stoddard would go on trips with her family, and she recalled fondly how she and her parents would observe birds in nature.

Today, Stoddard is Yale’s resident undergraduate ornithologist. This may seem strange — Yale offers few ornithology courses, much less an ornithology major — but since her freshman year, Stoddard has worked closely with biology professors in an out-of-class setting, studying birds and even making advances in the field.

Perhaps the most notable of her many achievements is a computer program she designed to help understand bird vision. The subject has long been of interest to ornithologists — while human eyes have three color cones, bird eyes have a fourth, allowing them to see ultraviolet colors. Birds see an entire world invisible to us.

“We tend to think that we’re at the top in evolutionary ways,” Stoddard says. “But birds have us beat in terms of color vision.”

Studying birds is important, Stoddard says, because migration patterns are often a direct gauge of environmental change. People take neighborhood birds for granted, but a change in their behavior provides a common-sense indication of natural shifts.

“Birds are in every backyard, in every city, every continent,” Stoddard explains. “It’s refreshing how broadening studying something as narrow as ornithology has been.”

Her ornithology work won her a Goldwater Scholarship in 2007, and after she graduates this spring, she will study at Cambridge University on a Marshall Scholarship. But for all the technical, interdisciplinary and even ground-breaking aspects of her work, the self-described “bird nut” is careful not to take herself too seriously.

“Some people may think ornithologists are just stiff people in white lab coats,” she says, “but they’re all really passionate about what they do.”

Stoddard’s own passion has taken her beyond the Yale labs to an island off the coast of Maine. There, at the Shoals Marine Laboratory, she spent last summer studying the reproductive behavior of the Herring Gull and the Lesser Black-backed Gull.

The fieldwork was dirty and dangerous.

Each day, Stoddard would wear a hard hat and carry a large stick to navigate through territory guarded by dangerous Greater Black-backed Gulls, only to crouch down for hours in a “hide” covered in gull “spats” and swarming with biting flies. But Julie Ellis, the Tufts University professor who supervised Stoddard, says her natural sense of humor helped her through the sometimes-trying experience.

“She really adjusted to the ‘icky’ aspects of fieldwork,” Ellis wrote in an e-mail. “For instance, sitting in a stinky blind with flies! This is a very different experience from lab work at Yale!”

Stoddard’s unflagging optimism has taken her through lab work and fieldwork, and at the Peabody, she has a chance to share her enthusiasm with others when she works as a tour guide. She especially loves talking to children, whose comments are always surprising.

“Kids always ask, ‘Couldn’t you just put on goggles to see like birds do?’” Stoddard says.

She adds with a laugh: “It’s a bit more complicated than that.”