Construction on the real retirement community – Mercy Auburn Senior Community, a complex of 60 affordable senior apartments for the public – began a few weeks ago just down the hill from the cluster of Spanish colonial buildings making up the Sisters of Mercy convent and retreat center in Auburn.

But these days, the mother house of the largest order in the Sacramento area is a de facto senior community, as well. Of the 64 Sisters of Mercy in the Sacramento Diocese, 25 have returned to live out their days at the Auburn convent. Their average age is in their early 70s.

The convent, founded more than 150 years ago, clearly wasn't intended as retirement housing: In the late 1950s and early 1960s, its dormitories were bursting with young women sent over from Ireland to take their vows.

"We had such an overflow that women coming into religious life were hanging out the windows," said Sister Eileen O'Connor, 76, who entered the convent at 18.

Over time, the Auburn convent has slowly aged its way into becoming a residence for older women who have devoted their lives to the church. With the aging of America's Roman Catholic religious orders, mother houses in every corner of the country have become unintentional retirement homes for nuns.

Demographics drive the trend – primarily, a decades-long drought of young people interested in joining, as the typical older nuns did, at 18.

The average age of American nuns is 74, according to the Leadership Conference for Women Religious, which represents 80 percent of American orders, while the average age of new sisters making permanent vows is 39.

According to Georgetown University's Center for Applied Research in the Apostolate (CARA), there were almost 180,000 Roman Catholic sisters in the United States in 1965. Today's number is one-third of that.

"Rumors of our demise are exaggerated, but it's also true there will be a huge demographic shift in the next 10 to 20 years," said Sister Christine Schenk, a member of the Sisters of St. Joseph and executive director of Ohio-based FutureChurch, a progressive church advocacy group.

"A lot of our work is to assure that we leave a legacy that continues. We have a lot of women leading as lay ministers, and sisters paved the way for them."

Aging population of nuns

Sister Mary Padilla, who entered the Auburn convent in 1947, remembers its vast front steps filled with sisters, both young and old, posing for a photograph.

"We were pretty much isolated by ourselves," said Padilla, 85, who retired in 2000 from teaching but continues volunteering, counseling prisoners at the Sacramento County jail. "The cows would come moo at us.

"It was a time for rules and regulations. There were rules for everything. You were informed in obedience, and you never questioned."

The reasons that church experts give for the decline in orders' membership numbers amount to a quick outline of a half-century of change in American society and modern Catholicism.

As women began entering the workforce in larger numbers in the 1960s and 1970s, they took on many of the roles that many nuns traditionally performed in American life: Sisters of Mercy, for example, are called to teach, nurse and work with the poor.

"Years ago, there were not options for women other than motherhood or religious life," said Sister Janice Bader, executive director of the National Religious Retirement Office. "Mothers were stay-at-home mothers. Women attracted to something of service outside the home didn't have a lot of options."

CARA research shows that before 1960, about 23 percent of young Catholic women gave serious consideration to religious vocation, as opposed to 8 percent today.

The 1960s swept in calls for openness across society – including the reforms of the Second Vatican Council, or Vatican II, which modernized the church and religious orders.

By late 1966, many of Auburn's Sisters of Mercy began wearing modest street clothes rather than habits.

Sisters moved out of convents, many living in small apartments. They earned advanced degrees, and they became theologically more progressive.

As Padilla said: "Bended knee, give thanks to Vatican II. That's why we are today free and independent adult women."

About half of American nuns re-evaluated their calling, leaving the convent for secular life. And numbers began to drop.

Some experts suggest that the huge numbers of women entering religious orders halfway through the 20th century really amounted to a statistical aberration.

"It was unprecedented in church history," Schenk said. "And it set up an expectation that could not be sustainable."

Interestingly, a recent CARA study shows that younger, newer nuns – average age 32 – express a desire for a return to tradition, structure and obedience.

"Younger people today are saying they want more structure," said Sister Michelle Gorman, 60, who was the sole novice arriving from Ireland in 1971 to enter the Auburn convent. She now lives in Omaha as part of the leadership team of the Sisters of Mercy's West Midwest Community, which stretches from Detroit to California.

"When I entered, it was on the cusp of not as much structure. People were leaving, so now we try to help people discern their calling. It's not about having enough bodies to work in the schools or hospitals. Consequently, there will be fewer people, but they will stay for the right reasons."

A 'model for the world'

About 150 sisters from the West Midwest Community, one of five Sisters of Mercy regions in America, have died since the community was formed in 2008, Gorman said. The Auburn mother house has lost two sisters in the past year. One was 76, the other 95.

At the convent, just as at any comfortable retirement residence, separate rooms are set aside for arts and crafts, computer use and working out on treadmills and stationary bikes. A notice for chair exercise class is tacked to a hallway bulletin board.

"See you there!" the notice instructs residents.

And sure enough, midway through a cool, sunny morning in the foothills, a seated older woman raises and lowers her arms in the convent's solarium while a volunteer cheerfully issues instructions.

Turn left down the hallway, and there's the infirmary – the skilled nursing center, complete with a set of doors that can be locked to protect dementia patients given to wandering. Here, 10 aging sisters receive round-the-clock nursing care.

Another 15 nuns live in private rooms just upstairs from the infirmary, whose patients are mostly in their 80s. The order's oldest Auburn resident is 90.

In return for their decades of service to the church, the order cares for their old-age needs at the convent.

"We want to model for the world how to grow old gracefully and how to take care of elderly people," said Gorman.

"We want our sisters to go up and enjoy the place and not wait until they're ill and have to go straight to skilled nursing. We want them to know that their life is more than their ministry and good work."

Padilla, for one, plans to return to Auburn only when she isn't healthy enough to continue her jail ministry. She lives for now at the Holy Spirit convent in Land Park.

But Sister Margaret Walsh, now 83, returned to Auburn from Redding in 2000 when she retired from teaching. Along with O'Connor, she volunteers as a spiritual director for church members seeking guidance.

"We don't retire as long as we're physically able," she said.

O'Connor returned three weeks ago from Sacramento, because most of her ministry's clients are in Auburn.

"I've been up and down, but my heart has always been here at the convent," she said. "This is where we were born into religious life."

© Copyright The Sacramento Bee. All rights reserved.

• Read more articles by Anita Creamer