The only member of the genus Pooecetes, it is a pale sparrow with brown streaks that breeds across the grasslands of northern North America.

The vesper sparrow was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[2] Gmelin based his own description on those for the "grass finch" that had been described by John Latham in 1783 and by Thomas Pennant in 1785.

[3][4] The vesper sparrow is now the only species placed in the genus Pooecetes that was introduced in 1858 by the American naturalist Spencer Baird.

[9] Another notable characteristic is that some vesper sparrows, especially west of the Cascades, tend to have a more pinkish hue.

[10] The male sings from a higher perch, such as a shrub or fencepost, which indicates his ownership of the nesting territory.

[11] Vesper sparrows tend to be more grounded to the shrub area, often taking dust baths and hopping around.

[12] The courtship involves the male sparrow running with his wings raised and occasionally jumping around to sing its song.

Improper cultivator operations including early and frequent harvesting have destroyed nests and eggs.