Migratory Status: Short-distance migrant
PIF Population Estimate: 
140 000 000
Percent of western hemisphere population breeding in boreal forest: 85%
BAM Effective Detection Radius (m) : 95.17
PIF Maximum Detection Distance (m) : 200
Canadian BBS Population trend: -0.7 (-1.1 to -0.2)
Life History
The White-throated Sparrow is one of the most abundant and widely distributed songbirds in the boreal forest region of North America. Its song, “Oh-sweet-Canada-Canada-Canada"", is synonymous with the forested regions of Canada’s boreal. Being a short-distance migrant, the species is also a common visitor to bird feeders throughout its wintering range in the southeast United States.
Adults occur in two distinct colour morphs, which were originally thought to represent sexual differences. The species is now known to be polymorphic, as both sexes can be separated into white and tan morphs, based on the colour of the median crown stripe. The polymorphism is correlated with behavioural differences. White-morph males are more aggressive, sing more and often seek more extra-pair copulations than tan-morph males. White-morph females also sing. Tan-morph males expend more energy providing food for the young. In addition to this complex polymorphism, the species also mates disassortatively, where white-morphs typically mate with tan-morphs, thereby maintaining the polymorphism. Evidence suggests that this polymorphism is stable, as populations across the breeding range have continued to maintain an almost 50:50 morph ratio.
The White-throated Sparrow’s breeding range extends over most of the forested boreal forest, from Newfoundland to the southeast corner of the Yukon Territory. The breeding range also extends south into mixed and deciduous-dominated forests associated with the Great Lakes and the Appalachian Mountains. The winter range includes most of the United States, with the greatest numbers occurring south and east of the Great Plains. Some partially migratory populations exist in the southeastern portion of the breeding range and disjunct wintering populations occur in Oregon and California.
The White-throated Sparrow occurs throughout the forested regions of Canada’s boreal forest. The species has been known to utilize all successional stages of pure and mixed stands of both conifer and deciduous tree species. It appears to prefer areas with low, dense understory vegetation, such as those regenerating after disturbance, or emerging in older forests following canopy tree gap dynamics.
Reference(s)
Falls, J. B., and J. G. Kopachena. 1994. White-throated Sparrow (Zonatrichia albicollis), The Birds of North America, No. 128. A. Poole and F. Gill, eds. The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists's Union, Washington, D.C.
