Closeup of Brown Booby over Magen's Bay

The cloaca of a Brown Booby. Note that it's the small dot just before the bird's feet.

Cloacal pecking of the Dunnock

Dunnocks performing cloacal pecking.

Cloaca (kloh-AY-kah; from Latin, a sewer[1]): the combined opening of the digestive, urinary, and reproductive systems of many vertebrates, including monotremes, birds, fish and reptiles; also in some invertebrates.[2]

In birds

In birds, urine and feces from the digestive tube, and sperm and eggs from the reproductive organs, all pass out of the body through a common passage, the cloaca.[1]

The cloaca is incompletely separated into three compartments: the copropodeum, into which the large intestines empties; the urodeum, into which the ureters and genital ducts empty; and the proctodeum, with which the coprodeum and urodeum communicate and which opens to the outside of the body through the vent, or anus, which is the external opening of the digestive tract.[3][1]


  1. ^ a b c Terres, John K. (1980). The Audubon Society Encyclopedia of North American Birds. Alfred A. Knopf, Inc. ISBN 0394466519. 
  2. ^ France, Peter, Guerrero, Angeles Gavira; et al. (2006). Ocean. Dorling Kindersley Inc. ISBN 9780756636920. 
  3. ^ Berger, A.J. (1961). Bird study. New York: John Wiley & Sons, Inc.
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