[2] The northern parula is one of the smaller North American migratory warblers, often being one of the smallest birds in a mixed feeding flock besides kinglets or gnatcatchers.

[4] The genus name Setophaga is from Ancient Greek ses, "moth", and phagos, "eating", and the specific americana is Latin for "American".

[5] This species is migratory, wintering in southern Florida, northern Central America, the West Indies and most of the Lesser Antilles.

They have been extirpated as a breeder from much of the Midwest as well as from many areas in Massachusetts, New Jersey, Connecticut, New York, Rhode Island and Vermont.

Explanations for the disappearance may be changes in habitat or increasing air pollution, which limited the growth of epiphytes on trees that the warbler depended on for nesting.

A further explanation is the clear-cutting and bog draining that have significantly reduced the amount of suitable habitat in eastern North America.

This species constructs its pendulum nests in hanging vegetation and so it is often attracted to suspended clumps of moss or coniferous twigs that are more abundant in moist spruce bogs or hemlock swamps.

Prey items include spiders, damselflies, locusts, bugs, grasshoppers, aphids, beetles, caterpillars, flies, wasps, bees, and ants.

[6] A northern parula from Augusta, Georgia was found to be a host of an intestinal acanthocephalan worm, Apororhynchus amphistomi.