Foreclosure activity plunged more than 60 percent across the region in the first quarter in response to rising home prices, a strengthening economy and a government assistance program that kicked in Jan. 1, a market tracker said Tuesday. Mortgage defaults and foreclosures fell by large amounts across the state, said La Jolla-based DataQuick. "Foreclosure starts were already trending much lower late last year because of rising home prices, a stronger labor market and the settlement agreement between the government and some lenders.