The Seaside Cinclodes is a curious passerine, as it may be one of the few passerines that can categorically be described as a "seabird." The Seaside Cinclodes is found strictly within the splash zone on the Pacific Coast, and it breeds, feeds, and essentially leads all of its functions within the spray from the sea. It is physiologically adapted to deal with food and water of high saline concentration, and in all ways is as more of a seabird than many species of cormorants and gulls. Currently the Seaside Cinclodes is considered a species separate from the Surf Cinclodes (Cinclodes taczanowskii) of Peru. The distribution of these two species is divided by a very long sandy beach area between northernmost Chile and southernmost Peru; both of these cinclodes are restricted to rocky coastlines, thus this sandy stretch is a major barrier. The northernmost populations of Seaside Cinclodes near Arica, Chile are paler, however, and show a greater tendency to have a full white supercilium, unlike more southern birds. Seaside Cinclodes are endemic to Chile, and sometimes are referred to as Chilean Seaside Cinclodes. Molecular data clarifies that the two species of "seaside" cinclodes form a group with the more southern Dark-bellied Cinclodes (C. patagonicus).