Juvenile Chipping Sparrows are prominently streaked below. Like nonbreeding adults, they show a dark eye-line, extending both in front of and behind the eye. The brownish cap and dusky eyebrow are variable but generally obscure in juveniles.
The flight call of the Chipping Sparrow is heard year-round. Its flight call is piercing and pure-tone, lasting about 50 milliseconds. It starts out around 9 kHz, then falls to 7 kHz, then rises again to 9 kHz. The flight call may be transliterated as 'seen?' Chipping Sparrows migrate by night, and their flight calls are a characteristic sound of the night sky in spring and fall in the United States. In the southern Rockies and eastern Great Plains, the Chipping Sparrow appears to be the most common nocturnal migrant, judged by the number of flight calls detected per hour. On typical nights in August in this region, Chipping Sparrows may be heard at a rate of 15 flight calls per hour. On better-than-average nights, Chipping Sparrows occur at a rate of 60 flight calls per hour, and on exceptional nights Chipping Sparrows flight calls are heard more than 200 times per hour.
At least two subspecies of Chipping Sparrows occur in western North America. The widespread Spizella passerina arizonae is associated with mountains and arid habitats of the western interior. A Pacific slope population constitutes subspecies S. p. stridula. Although these two races are both western, and are often lumped together as the Western Chipping Sparrow, they do not necessarily form a single entity that stands apart from the Eastern Chipping Sparrow (S. p. passerina).
Throughout the year, Chipping Sparrows forage on the ground, often in loose flocks. Their diet consists mainly of seeds and crumbs of mostly any food, especially those fallen on the ground. Chipping Sparrows frequently forage directly from forbs and grasses, too. At any time of the year, especially, in spring, Chipping Sparrows may be seen in trees, even up in the canopy, where they forage on fresh buds and glean for arboreal arthropods.
Although they are wary, Chipping Sparrows often allow close approach. A quiet observer can often get to within 50-100 feet of one or more Chipping Sparrows feeding on the ground. When spooked, Chipping Sparrows fly a short distance to the nearest tree or fencerow.
In early spring, the first migrants return from their wintering grounds in March, but the bulk of migrants arrives throughout April. Males set up territories right away, and their trilled songs make them conspicuous. Breeding begins as early as April, but again, most nesting activity occurs from late April to early May onwards.
Molt in the Chipping Sparrow follows the "Complex Alternate Strategy" as usual for American sparrows. It consequently has two molts per year as adults and three molts in their first year of life, also called their first plumage-cycle. The Chipping Sparrow's two adult molts occur in late summer and late winter.
Although this bird's original habitat was probably coniferous forest, especially the eastern subspecies has adapted well to the changes brought about by increased human population in its range.