The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season. More on reading these maps.
Across much of the U.S., the Tree Swallow is the hardiest swallow species. It returns early in spring, leaves late in fall, and winters in the southern U.S. According to Audubon's climate model, Tree Swallows will soon be wintering farther north and farther inland. The model predicts a 56 percent loss of current winter range, with some potential expansion during that season, but with some currently favorable areas along and near the Gulf Coast forecast to become less available for wintering Tree Swallows. A similar pattern is in store for summer: a 61 percent loss of current range, with the range drifting northward. Any northward spread will require nest sites: standing dead trees or human-supplied bird boxes.