Amid tight inventory, Sonoma County's housing market has gotten off to its slowest start in six years.

Buyers purchased 260 single-family homes in February, according to The Press Democrat's monthly housing report compiled by Pacific Union International Vice President Rick Laws. Last month, sales fell 11 percent from a year earlier.

For the first two months of 2014, buyers have purchased 535 houses. That is the lowest number since 347 homes were purchased for the same period in 2008, a time when prices were tumbling sharply.

"Without a doubt we're off to a slow start," Laws said.

Experts say housing is still going through a transition in the aftermath of a historic housing crash.

"The market has been driven by the investor buyer," said economist Christopher Thornberg, founding partner of Beacon Economics in Los Angeles.

Over the last year, investors have pulled back, he said. Eventually the market will shift more toward the "move-up buyer" who is selling a home in order to buy a more-expensive property.

"We're in between these two waves," Thornberg said.

The county's median price declined 2 percent from January to $449,825. The median still increased 18 percent from a year ago.

During the last decade, the county's median price reached a record $619,000 in August 2005, before falling to a low of $305,000 in February 2009.

Agents said buyers have remained on the hunt for homes this winter. But sales are constrained by a continued lack of supply.

"It's just remarkable how the inventory has shrunk," said Mike Kelly, an agent with Keller Williams in Santa Rosa.

February ended with fewer than 600 homes for sale, slightly more than a two-month supply of inventory at the current sales pace.

Five years ago, the housing inventory amounted to roughly a five-month supply, but for the last year it has hovered at or near the two-month level. That remains considerably lower than the roughly six-month supply that experts say is needed for a balanced market.

The lack of inventory was blamed for the slowest February sales in six years across the entire Bay Area.

Buyers purchased 4,963 houses and condominiums in the nine-county area last month, a decline of 8 percent from a year earlier, according to real estate information service DataQuick.

While citing various factors for the slowdown, DataQuick President John Walsh said in a statement that "clearly the main culprit is an inadequate supply of homes for sale."

The Bay Area median sales price last month increased nearly 3 percent from January to $540,000. The median increased 33 percent from a year earlier.

In Sonoma County, sales of foreclosures and short-sale properties has declined. Short sales are properties sold for less than the amount owed on the mortgage.

To date this year, such distressed sales have made up just 12 percent of all homes sold, compared to 34 percent a year ago.

Many of those distressed properties were among the cheapest homes on the market. The drop in availability has led to a sales shift toward more expensive homes — a change that has contributed to higher median prices.

To date this year, sales of Sonoma County homes priced under $300,000 have declined 73 percent from a year earlier. Meanwhile, sales have increased 79 percent for homes priced at or above $700,000.

Agents expect more homes on the market as the traditional spring sales season gets under way. Even so, many potential sellers have two reasons for taking their time, said Maria Lounibos, a broker with Sotheby's International Realty in Sonoma.

Some sellers, she said, are betting on rising prices and thinking, "If I can get 600 today, six months from now I can get 650."

As well, sellers want to make sure they can buy another place before they agree to part with their current home.

"What can I sell them?" Lounibos asked. "Unless they come live with me, I have nothing to sell them."