In 1758, Linnaeus classified the Northern Parula as a tit, Parus americanus, and as taxonomy developed the genus name was modified first to Parulus and then the current form. The family name, Parulidae, of course also derives form this source.
The four species are:
The first two of these are sometimes placed in the genus Vermivora. The two named as parulas are very closely related and form a superspecies.
Parula warblers are tiny, 11-12 cm long. They have yellow, orange or red throats, with the colour extending further down the underparts in some species. The upperparts and wings are various shades of grey or blue-grey, and the mantle is greener or blacker than the rest of the back.
The breeding habitat is woodlands with clearings. These warblers nest low in a tree or on the ground, laying 3-7 eggs in a cup nest.