Naturalist has noted eastern chipmunk's winter appearance for 50 years By JIM GILBERT, Special to the Star Tribune March 4, 2021 — 6:07pm Text size Copy shortlink: For 50 years I have recorded in my nature notes when the first active eastern chipmunk appeared above ground in Carver County. Observations of that happening have come from our Waconia yard, Victoria, Lowry Nature Center in Carver Park, and the University of Minnesota's Landscape Arboretum. All in the same county. Many friends have helped with the long list of dates, so the results are a real team effort. The big day for the first eastern chipmunk seen above ground is usually close to the last week in February or first week in March, the beginning of their mating season.