About Spizella passerina (Bechstein, 1798)
This species, Spizella passerina, has consistent year-round adult base coloration: the underparts are gray, and the upperparts are orangish-rust. Adults in alternate breeding plumage have a reddish cap, an almost white supercilium (eyebrow stripe), and a black trans-ocular line that runs through the eye. In basic nonbreeding plumage, adults have less distinct markings, with a brownish cap, a dusky eyebrow, and a dark eye-line. Juvenile chipping sparrows have prominent streaking across their underparts. They share a dark eye-line with nonbreeding adults, and this line extends both in front of and behind the eye. For juveniles, the brownish cap and dusky eyebrow are variable in appearance, but are generally obscure. Standard measurements for the species are: length 4.7–5.9 inches (12–15 cm), weight 0.4–0.6 ounces (11–17 g), and wingspan 8.3 inches (21 cm).
