The wallcreeper (Tichodroma muraria) is a small passerine bird found throughout the high mountains of the Palearctic from southern Europe to central China. It is the only extant member of both the genus Tichodroma and the family Tichodromidae.
Its plumage is primarily blue-grey, with darker flight and tail feathers. Its most striking plumage feature, though, are its extraordinary crimson wings. Largely hidden when the wings are folded, this bright colouring covers most of the covert feathers, and the basal half of the primaries and secondaries. The subspecies T. m. nepalensis is slightly darker than the nominate race.
Though largely silent, both male and female wallcreepers sing, the females generally only while defending feeding territories in the winter. The song is a high-pitched, drawn-out whistle, with notes that alternately rise and fall. During the breeding season, the male sings while perched or climbing.