Two sub-freezing nights prompted rock bass and smallmouth bass to migrate from their 36-degree stream into a spring branch with 54-degree water. Warmer water increased their metabolisms to the point they were actively feeding. Mini-Minnies and Ozark Woolly Buggers brought a dozen of each species to hand. Even a small spring will attract fish and furnish great action. A stream thermometer enables anglers to locate winter hotspots.