Despite this wide range, numbers of the Clapper Rail are now very low on the west coast, because of destruction of its coastal marshland habitat. Its largest western population, of something under 3000, is in San Francisco Bay; there is a small inland population along the Colorado River. On the east coasts, populations are stable, although the numbers of this bird have declined due to habitat loss.
The Clapper Rail is a chicken-sized bird that rarely flies. It is grayish brown with a pale chestnut breast and a noticeable white rump patch. Its bill curves slightly downwards.
These birds eat crustaceans, aquatic insects and small fish. They search for food while walking, sometimes probing with their long bills, in shallow water or mud.
Some researchers believe that this bird and the similar King Rail are a single species; the two birds are known to interbreed.