I alt behandles 75 gjerdesmett-, 34 thrashers og 5 fossekallarter.
Fra forlagets egen omtale:
This guide looks at three distinctive passerine families, covering 75 wrens, 34 thrashers and 5 dippers. The wrens display great diversity, occupying almost every kind of habitat in the Americas. The thrashers include the mockingbirds, catbirds and tremblers, and the dippers are river specialists.