Caroline Wall volunteers to be available once a month for a middle of the night call if disaster strikes the metro area. But the retail manager spent a recent day off from work making some urgent phone calls herself.

It's crunch time for nonprofits such as the American Red Cross Mile High Chapter, one of the many charities that relies heavily on December donations to fund much of the work it does in the community all year. The economic downturn has added extra urgency to its fundraising appeal this year.

"We know these are pretty difficult times," said Wall, who joined other Red Cross volunteers last week to make phone calls from a room previously used only for incoming phone calls from residents hit by area catastrophes. "Some people are saying they're not in a position to give this year."

The Denver-based nonprofit came in shy of its November target. With two weeks to go, it has raised about $150,000 toward its December goal of $500,000. The average donation it receives: $50.

"This is the classic example of what we refer to as 'all hands on deck,' " said Charley Shimanski, who became the new CEO of the Red Cross chapter last month. "The public doesn't realize we get no government funding."

All over Colorado, charities have been engaged in the year-end push to raise money. For those in health and human services, demand for charitable services has increased because of the hardships people face as they lose their jobs or homes.

"I've heard from several nonprofits that donations are flat or down while the need is up," said Sharon Knight, the interim president of the Colorado Nonprofit Association, the trade group representing the organizations that make up the state's huge charitable sector.

Arts and cultural groups also are bracing for expected cutbacks in foundation giving and other support.

The Curious Theatre met its end-of-year fundraising goal with a matching grant from the Gay and Lesbian Fund. But it purposely avoided making a big plea for gifts from its existing donors. Instead, it will wait until early next year to offer expanded benefits to members who contribute at a certain level.

"It's always difficult as a fundraiser to compare yourself to people who need shelter and food," said Diana Gatschet, development director for the contemporary theater company. "But, in times like these, we are able to improve people's quality of life and offer a temporary escape."

Many donors give at this time of year in a last-minute attempt to ensure they can claim a deduction when they file their tax returns in April. Charitable gifts also tend to increase around the holidays.

But this year is proving to be an especially challenging time to ask for money.

"We're all vying for the same donors and their ability to give," said Planned Parenthood's Gail Kelley, who huddled with other nonprofit executives at the Allied Jewish Federation last week to swap stories and concerns about a slowdown in charitable giving.

A survey conducted this fall by the Colorado Nonprofit Association revealed that many residents said they would be unable to give as generously this year because they're supporting friends and family in need.

Boys & Girls Clubs of Metro Denver expects revenues to be down about 25 percent. "People are still being very generous but by and large people are giving less," said CEO John Arigoni. "They are making choices and narrowing their gifts to one or two groups."

Still, "the sky is not falling," he said. "We've been around 47 years, and we're going to be around in another 47. Things are tougher, that's all."