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.
When birders glimpse a Black Guillemot from the foggy Maine coast, they are seeing the species at the edge of its range. The vast majority of these birds in North America occur in remote districts of northeastern Canada, with smaller numbers in Alaska. Audubon's climate model, looking only at the winter range, forecasts both an overall decrease in acceptable climate and movement inland of suitable conditions. The Black Guillemot is adaptable, having recently colonized the newly created volcanic island of Surtsey, off the coast of Iceland. Its non-breeding ecology is strictly limited to marine and coastal habitats, however, and it seems unlikely that the Black Guillemot will track climate change inland.
Are the projected range maps different from the range maps in field guides? Find the answer here.