With a Virginia Rail. Almost a duet, it seems that the Black Rail is really leading this, its calls fairly evenly spaced.
They breed here, there were three adults counter-calling at this location.
Following the Cornell Birds of the World species account, which in turn follows Ripley (1977) and Fjeldsa (1983):
SUBSPECIES
Laterallus jamaicensis coturniculus Scientific name definitions
Systematics History
L. j. coturniculus (Ridgway, 1874), the California Black Rail [type locality = Farallon Islands, California].
Distribution
Largely resident in southwestern North America, from central California south to northwestern Baja California and inland east to the lower Colorado River of western Arizona and northwestern Sonora.
Identification
Similar to L. j. jamaicensis, but dorsal chestnut patch extends onto back, crown chocolate brown, and bill more slender; averages smaller overall (Brewster 1907, Ripley 1977).
When they grow out of rock like this… they deserve some extra attention.