Drumlin Farm, Blue Hills Trailside, Broadmoor and Habitat run winter nature classes, animal encounters and vacation-week programmes all season.
Details change often — check with the program.
Mass Audubon is listed in the GOkidOZ guide to museum classes and family tours across Massachusetts. Class schedules, free hours and vacation-week programmes change term by term — check the official site above for current listings, and see what else is on during winter break.