Medium-sized warbler, light olive-brown above and yellowish below. Distinctive features include longish, daggerlike bill, long primary projection in the wings, and square tail. Told from similar Melodious Warbler by usually conspicuous pale wing panel, longer wings, and marginally shorter bill. Usually difficult to see when singing except during song flights, when long wings are apparent. Found in tall forest with oaks and birch, mixed forest, gardens, and parks. Song is fast, loud, and melodious with lots of mimicry.