The dipper is Britain only aquatic songbird, walking along stream beds to catch invertebrates and facing threats from acidification.
Dippers are extremely sensitive to water acidification, which reduces aquatic invertebrate populations that form their food source. Afforestation with conifers has acidified many upland streams in Wales and Scotland. Flood events can destroy nests, and chicks can drown if water levels rise suddenly. Agricultural pollution through sheep dip and slurry also impacts food availability.