The Rock Wren is well named. Most descriptions of Rock Wren habitat mention "rock" for this pale wren of arid, western North America -- from southern Canada south to Costa Rica. Rock Wrens are more easily heard than seen, their songs are unmistakable. Males are truly remarkable singers, and can have large song repertoires of 100 or more song types, many of which seem to be learned from neighbors.
Much information about this wren's biology is anecdotal. One curious aspect of this wren's biology has received much notice but virtually no study: Rock Wrens usually build a pavement or walkway of small, flat stones or pebbles that leads to the nest cavity. The nest is usually located in a rock crevice, occasionally far out of sight, but the pavement may give an external sign of the nest's location. The function of this pavement is open to speculation.