There are a number of Passeriformes (perching birds) called warblers. They are not necessarily closely related to one another, but share some characteristics, such as being fairly small, vocal, and insectivorous.
They are mostly brownish or dull greenish in color. They tend to be more easily heard than seen. Identification can be difficult and may be made on the basis of song alone. To English-speaking Europeans, warblers are the archetypal "LBJs" (little brown jobs).
- "Old World warblers", formerly all in family Sylviidae
- Leaf warblers, now in family Phylloscopidae
- Typical bush warblers, now in family Cettiidae
- Grass warblers and megalurid bush-warblers, now in family Locustellidae
- Marsh and tree warblers, now in family Acrocephalidae
- True warblers or sylviid warblers, remaining in family Sylviidae or moved into the Timaliidae
- Malagasy warblers, the newly assembled family Bernieridae
- Cisticolid warblers, family Cisticolidae
- Tit-warblers or flycatcher-tits, family Stenostiridae
These are closely related to the titmice and chickadees
- Australasian warblers, family Acanthizidae
- Hawaiian honeycreeper—warbler-niched-(adaptive radiation), genus H. virens–common amakihi. (See: List of adaptive radiated honeycreepers)
- Wilson, Eisner, Briggs, Dickerson, Metzenberg, O'Brien, Susman, & Boggs. Life on Earth, Edward O. Wilson, Thomas Eisner, Winslow R. Briggs, Richard E. Dickerson, Robert L. Metzenberg, Richard D. O'Brien, Millard Susman, William E. Boggs, c 1973, Sinauer Associates, Inc., Publisher, Stamford, Connecticut. (hardcover, ISBN 0-87893-934-2)