The Thick-billed Warbler is a small brown bird with rufous on its crown and tail. It stays concealed in dense grass and shrubs and moves between breeding and wintering areas.
The crown and tail are rufous, the upperparts brown, and the underside pale. Its bill is stout and curves down at the tip.
It searches slowly while concealed in dense vegetation. It migrates seasonally between northern breeding areas and more southerly wintering grounds.
An extinction-risk assessment has not been added yet.