Yellowish-bellied Bush Warbler Horornis acanthizoides

Small, shy songbird of higher-elevation thick edges and secondary growth. Similar to Brownish-flanked Bush Warbler but with a paler, much more contrasting supercilium, a yellowish suffusion to the underparts, and a different song: male repeats a high thin note over and over, ascending to an extreme climax, before giving a shorter, less intense series of trilling, descending notes. Endemic Taiwan subspecies (concolor) sometimes considered a full species.