A bright-eyed, hefty billed bird of forests and to a lesser extent scrublands. Tends to hold its tail cocked up and wings drooped, especially when feeding. Mostly gray with a blackish mask and whitish underparts. Brown Trembler is largely warm brown, lacks white underparts of Gray Trembler and has a weaker mask, if any. White-breasted Thrasher is dark brown above and largely bright white below with a dark red eye (not yellow as in Gray Trembler). Song is a slow jumble of rich whistles and high-pitched sibilant notes. Calls include scattered whistles and harsh scolding notes.