This is a small tit, only 10.5 cm long. It is called "bushtit" but this depends more on the genetic relationship with the European Long-tailed bushtit (Aegithalos caudatus) than the size of its tail. It is divided into six subspecies This subspecies iredalei, is the westernmost with the subspecies' characteristic white line behind the eye (where other subspecies have black) and the uniformly rust beige underside.