not sure of ID, had thought maybe it was a female Red-winged Blackbird but the breast markings are not striped enough...
Savannah looks most likely to me, which undoubtdlymeans its a Song, or someother species entirely.
The Savannah Sparrow (Passerculus sandwichensis) is a small American sparrow. It is the only widely accepted member of the genus Passerculus. Comparison of mtDNA NADH dehydrogenase subunit 2 and 3 sequences indicates that the Ipswich Sparrow, formerly usually considered a valid species (as Passerculus princeps), is a well-marked subspecies of the Savannah Sparrow, whereas the southwestern Large-billed Sparrow should be recognized as distinct species (Passerculus rostratus).