When Sheena Bowa was 3, she traded her tricycle for a dog.

"It just followed me home," she explained to her mother, neglecting to mention the swap.

Her mother, reasoning that not too many strays come equipped with a leash, quickly reversed the transaction.

Bowa's first pet was a cat, and a cocker spaniel and black spitz followed. When she was married to Larry Bowa, the former Phillies shortstop, he knew exactly how to celebrate their first wedding anniversary. He gave her a cocker spaniel, which Sheena named Muggsy.

One day in the '70s while Sheena was watching a Phils game at the Vet, a German shepherd stray suddenly appeared beside her aisle seat and gave her a look she couldn't resist. Sheena adopted him and paid a vet to restore his health.

Today, Bowa, 60, a real estate agent, shares her Radnor house with four cocker spaniels, including three rescues, and a stray cat.

"I love animals," she says. "It's my passion."

Lately, that passion has expanded to include the Francisvale Home for Smaller Animals, a largely hidden Main Line gem that is celebrating its 100th anniversary. Bowa, a volunteer and board member, is helping stage a centennial gala Saturday in the Crystal Tea Room at the Wanamaker Building.

"It's small and intimate," Bowa says of Francisvale. "The staff knows the names of all the animals, and the dogs are walked every day. It's easy to jump on a bandwagon that's already going someplace, but I've always rooted for the underdog, and this place needed help. There wasn't even a sign out front. Word has got to get out."

Francisvale occupies 16 hilly acres on Upper Gulph Road in Radnor. A white shingled cottage with a porch houses offices and most of the cats. In a separate stucco building there are air-conditioned dog kennels with access to outdoor runs.

Those who pass by might be familiar with its pet cemetery, where stone monuments on a woodsy slope mark the graves of more than 2,000 beloved Fidos and Felixes, as well as a couple of horses, a monkey, and, legend has it, the remains of the MGM lion. But relatively few people, including neighbors, realize that Francisvale claims to be the oldest continuously operated no-kill shelter in the United States.

Francisvale was inspired on New Year's Eve 1897 when George McClellan and his wife, Harriet, were riding in their carriage to the theater in Philadelphia. On the way, they noticed a puppy shivering next to a snowbank. They adopted the dog on the spot and named him Francis. So fine a pet was Francis that Harriet McClellan was inspired to help other stray dogs. After supporting a couple of shelters in town, she acquired the land and cottage in Radnor. Francisvale opened its doors to dogs in 1909 and began accepting cats in 1980.

Today, the refuge can accommodate 25 dogs and 45 cats.

"We are always at overcapacity," laments executive director Grace Kelly, 35, who came to Francisvale from the development staff at the Philadelphia Zoo.

Dogs stay an average of three months before finding homes. Cats, which are harder to place, can remain for years.

"Dogs tend to suffer more physical abuse," Kelly says. "Cats are seen as more disposable."

Making himself comfortable in the shelter's office now is a 15-year-old, tan-and-white longhair cat named Harry. Another newcomer is Leo, a handsome coonhound rescued from a hoarder in Kentucky.

"There's a high burnout rate in this job," says Kelly, "because you see the dark side of humanity. But there's also a wonderful positive side. The trick to surviving is to focus on the good people and where these animals are going instead of where they came from."

Like many old-line Philadelphia institutions with aristocratic roots, Francisvale was modest about its good deeds and loath to promote itself. The reluctance was not only cultural but also practical. Publicity, it was feared, might lead to a deluge of animals, well beyond the shelter's capacity. Abandoned cats might be tossed over the fence, dogs chained to the gates.

About three years ago, Francisvale's board was invigorated by new blood. A fresh staff was hired, with the aim of modernizing the place. Kelly cites many improvements. Better applicant screening has meant better matches and fewer pet returns. (At one point, the return rate was 50 percent.) Dogs are now fed twice a day. They have blankets and are tucked in every night with a toy. The number of volunteers has jumped from five to 80, and they're trained by professional dog handlers. Cats have been liberated from their cages and are free to roam.

Next weekend's gala is indicative of another effort. After years of complacent obscurity, Francisvale is raising its profile, making itself known. Dogs looking for homes advertise their availability in Wayne's popular Memorial Day parade. Nodding to the digital age, Francisvale even has a Facebook page, with 300 friends.

"The mentality has changed," says Kelly. "We need as many people as possible to know about us, to know about the good work we do here."

Francisvale's annual budget is about $500,000, all from donations. Over the years, it has enjoyed the support of businesses such as Bryn Mawr Trust and John B. Ward & Co. tree service, which tends the grounds. Once a year, students from Villanova University rake, clean, and paint as part of their community-service day.

"People are so willing to give," marvels board president Melanie Shain.

Still, the shelter's endowment is meager, and many repairs and projects await attention. Shain, 62, of Wayne, has a background in investment management. Her chief goal: "to achieve financial stability so we will be here another 100 years."

In the meantime, she rejoices in the shelter's "wonderful, loyal volunteers."

Exhibit A: Sheena Bowa.

"If I could, I'd take all the sick animals home," she says. "They deserve to live someplace nice and to grow old with dignity."