Preen gland

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Cone-like prickly gland above the tail root (see arrow)

The rump gland ( lat. Glandula uropygialis ) is the only skin gland of many bird species . It is located on the upper side of the root of the tail, the rump . An oily secretion is formed in the bilobed, holocrine gland , which the bird distributes with its beak or its legs throughout its plumage. This regular greasing is an essential part of plumage hygiene, which preserves the suppleness of the plumage and makes it more water-repellent due to the better interweaving it ensures. The secretion also contains fungicidal and bactericidal components. The rump gland secretion may also play a role in the vitamin balance, as it contains vitamin D precursors. The main lipid component is a diester wax.

The rump gland is particularly developed in most swimming birds. In some birds, such as the hoopoe , the root gland is only fully functional in the early stages of development of the young birds; the secretion it releases is extremely bad-smelling and is also used to ward off predators. Symbiotic bacteria in the urinary gland secretion could contribute to the foul odor. Bacteria in rump gland secretions are otherwise only known in domestic turkeys ( Corynebacterium uropygiale ) and green tree hops ( Enterococcus phoeniculicola ).

Some bird species such as the emu , cassowaries , the great bustard and many parrots and pigeon species do not have a functional uterine gland in adulthood. With representatives of these genera, the plumage hygienic function of the rump gland is often replaced by so-called powder downs .

Carotenoid-containing rump gland secretions, which are applied to the plumage as a cosmetic color, are found in eight species of Asian hornbills and two species of pelicans . The pink plumage color of seagulls and terns during the breeding season is based on the deposition of astaxanthin pigments and not, as previously assumed, on the application of rump gland secretions.

literature

  • Eero O. Haahti, Henry M. Fales: The uropygiols. Identification of the unsaponifiable constituent of a diester wax from chicken preen glands . In: Journal of Lipid Research Vol. 8, 1967, ISSN  0022-2275 , pp. 131-137, online (PDF; 560 kB) .
  • Jürgen Jacob, Vincent Ziswiler : Chapter 4: The Uropygial gland In: Donald S. Farner, James R. King, Kenneth C. Parkes (Eds.): Avian Biology Vol. 6, Academic Press, Ney York 1982, ISBN 0-12 -249406-7 , pp. 199-324.
  • Anthony S. King, John S. McLelland: Anatomy of Birds. Basic features and comparative aspects . Ulmer, Stuttgart 1978, ISBN 3-8001-2468-8 , ( UTB for science, university paperbacks, agricultural sciences, biology, veterinary medicine 790), (original edition last: Birds. Their structure and function . 2nd Edition. Baillière Tindall, London 1984 , ISBN 0-7020-0872-9 ).

Individual evidence

  1. ↑ Markus Santhosh Braun, Stefan Zimmermann, Maria Danner, Harun-or Rashid, Michael Wink: Corynebacterium uropygiale sp. nov., isolated from the preen gland of Turkeys (Meleagris gallopavo) . In: Systematic and Applied Microbiology . tape 39 , no. 2 , p. 88-92 , doi : 10.1016 / j.syapm.2015.12.001 .
  2. ↑ Janette Law-Brown, Paul R. Meyers: Enterococcus phoeniculicola sp. nov., a novel member of the enterococci isolated from the uropygial gland of the Red-billed Woodhoopoe, Phoeniculus purpureus . In: International Journal of Systematic and Evolutionary Microbiology . tape 53 , no. 3 , 2003, p. 683-685 , doi : 10.1099 / ijs.0.02334-0 .