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.
Like the Cape May Warbler, this species benefits from outbreaks of spruce budworm on its breeding grounds in Canada. The Bay-breasted Warbler is already used to a partially nomadic lifestyle: it is common in some infested areas one year, and may be completely absent the next when budworms are not present. This adaptability should make the species more able to take advantage of a projected abundance of ideal climatic space should the adequate plant and insect communities colonize them. But the warblers will have to move quickly: only four percent of their current summer range is stable. Bay-breasted Warblers winter in in Middle America and northwestern South America.