Adult has jet-black coloration, a bright yellow bill, and red eyes and legs.
Sexes are alike, but male is slightly larger. Juvenile is a grey version of adult and has a black bill, pale throat and dull red to black legs.
Marshes with a thick cover of reeds and other aquatic vegetation.
A throaty 'chrrooo' and a rippling trill, 'weet-eet-eet-eet', uttered in duet.