The tree sparrow's crown and nape are rich chestnut with a kidney-shaped black ear patch on each pure white cheek; the chin, throat, and the area between the bill and throat are black. The upperparts are light brown, streaked with black, and the brown wings have two distinct narrow white bars. The legs are pale brown, and the bill is lead-blue in summer, becoming almost black in winter. This sparrow is distinctive in that it has no plumage differences between sexes.
A common sighting at the USRC, it is a year-round resident and also likely to nest in the gardens.