Dippers are the only truly aquatic passerine birds, walking and swimming underwater to find invertebrate prey. They are sensitive indicators of clean, fast-flowing upland river systems.
Dippers are highly sensitive to changes in water chemistry and macroinvertebrate community composition. Acidified rivers, over-abstracted streams and those affected by intensive agriculture support insufficient invertebrate prey. Climate change is increasing spate flood frequency, which destroys first nests and can flood burrow nests. Dippers nesting in known territories show high site fidelity — disturbance during nest-building causes abandonment.