On Alaska's North Slope, dippers inhabit the ice-free spring areas in winter. The American dipper is highly territorial and may defend more than a half mile of stream in summer and as much as 1,000 feet of stream in winter. Territorial singing during winter, however, is quite unusual for any songbird. The dipper's song is very melodious and sounds like a long rendition of some of the best notes of thrushes and wrens. Both sexes may be heard singing during all months of the year except immediately after the young have left the nest.
Dippers feed almost exclusively underwater on larval forms of aquatic insects.
To a much lesser extent, dippers will feed on small fish and fish eggs. In addition, during times of peak insect emergence, dippers may be seen flying out, in flycatcher fashion, on short round-trips after insects or skimming the newly emerged insects from the water surface. Their solid gray plumage camouflages them as they run across boulders along streams. Their inaccessible nesting sites, ability to dive under water, solitary habits, and their habit of flattening out and remaining motionless on the surface of the water when danger approaches also make them difficult to see or catch. Identification and protection of these sites may be crucial to maintaining dippers in a particular watershed.