This bird is found typically at altitudes between 500 and 2,000 m (1,600 and 6,600 ft) in the undergrowth and thickets of ravines, forest edge, and other semi-open woodland including second growth and large gardens.

The white-eared ground sparrow is on average 17.5 cm (6.9 in) long and weighs 43 g (1.5 oz).

The throat and breast patch are black, separated by a thin rufous-grey line, and the rest of the underparts are mainly white with grey on the flanks.

North Nicaragua birds, M. l. nigrior, have a much broader black breast spot than the nominate Costa Rican form, and the northernmost of the three subspecies, M. l. occipitalis, has a grey crown stripe, obvious yellow supercilium, and very small breast spot.

It is usually in pairs, and is a shy species best seen at near or dusk, although easier to find than its skulking relative, Prevost's ground sparrow.