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.
Famously irruptive, the Red Crossbill may be abundant one year in a given location, and completely absent the next. That combined with its tendency to live in areas that are very sparsely populated by people makes data collection difficult. Audubon's climate model projection for what happens in the mountains of western North America follows the same pattern we see for other mountain-dwelling species: a major contraction as birds are forced to higher elevations by global warming. Its general predictions for severe contractions in summer and winter ranges (64 and 77 percent, respectively) seem broadly plausible.