Sonoma County home sales slowed in January as the number of available short sale and foreclosure properties sharply declined.

Buyers purchased 280 single-family homes last month, according to The Press Democrat’s monthly housing report compiled by Pacific Union International Vice President Rick Laws. Sales declined 16.7 percent from a year earlier.

Agents attributed the decline to a sales inventory at its lowest level in eight years.

“Right now we have a plethora of buyers and not enough to sell them,” said Stephen Liebling, manager of Coldwell Banker in Sebastopol.

January ended with a median sales price of $365,000. The median declined 6.4 percent from December but remained 12.9 percent above January 2012.

The housing market often slows in winter, but January sales were marked by a divergence between distressed properties and those in which the sellers held equity. Equity sales actually increased from January 2012. But the number of distressed sales was cut nearly in half.

As a result, the overall sales mix changed. A year earlier, one in every two houses sold involved a short sale or foreclosure. By last month that rate had declined to one in three.

The divergence was also seen in last month’s new home listings. The 236 listings of new equity properties were roughly the same as a year earlier. But the 105 new distressed listings represented a 54-percent decline from January 2012.

The total number of available homes for sale at the end of the month fell to its lowest level since January 2005. The inventory amounted to roughly a two-month supply at the current pace of sales — considerably lower than the six-month supply that experts say exist in a normal housing market.

The lack of listings was a concern at last month’s California Association of Realtors meeting at Monterey.

“Throughout the state, north and south, we heard the same thing: There is no inventory,” said Sally Crain, a broker associate with Century 21 Alliance in Santa Rosa.