Savannah Sparrow is the only member of the genus Passerculus. Precise subspecific identification is speculative outside the breeding season because of the high degree of individual variation within subspecies. Birds breeding here have been assigned to P. s. mediogriseus, but BNA, IOC and H&M now all consider P. s. savanna to be a synonym. Clements still recognizes mediogriseus distinguished from paler P. s. savanna (breeding in Nova Scotia) by its grayer, darker plumage with heavier streaking. It breeds from SE Canada through most of the NE and Mid-west United States. HBW merges most of the subspecies, recognizing only two, but splitting three SW races into separate species. Under this scheme, our bird would be nominate P. s. sandwichensis. Canon PowerShot SX50 HS.
References:
Dickerman, R. W. and K. C. Parkes. (1960). The Savannah Sparrows of Minnesota. Loon 32:110-113.
Rising, J., Christie, D.A. & Garcia, E.F.J. (2016). Savannah Sparrow (Passerculus sandwichensis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/61918 on 26 October 2016).
Wheelwright, N. T. and James D. Rising. (2008). Savannah Sparrow (Passerculus sandwichensis), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/savspa