The Cerulean Warbler breeds in mature hardwood forests in rocky terrain, largely limited in Canada to the Frontenac Axis and southern part of Georgian Bay, and occasionally in extreme southern Quebec. It overwinters in montane forests of South America, from Venezuela to Peru. The Canadian population estimate of approximately 980 individuals (range 866 to 1086) comprises <1% of the global population and represents a very low degree of responsibility for Canada. Data from the Breeding Bird Survey indicate a decline of more than two-thirds since 1970, but the rate of decrease has slowed down over time. The species was assessed as Special Concern by the Committee on the Status of Endangered Wildlife in Canada in 2003 (COSEWIC, 2003), and uplisted to Endangered in 2010 due to its small population and recent declines (COSEWIC, 2010). It has been listed as Endangered under the Species at Risk Act since 2017, and is considered to be below its goal range.