Experimental Test Of The Importance Of Preen Oil In Rock Doves (Columba Livia)

Most species of birds have a uropygial gland, also known as a preen gland, which produces oil that birds spread through their plumage when preening. The plumage of waterfowl deprived of uropygial oil becomes brittle and is subject to breakage. For other groups of birds, however, the importance of preen oil remains unclear. Previous workers have argued that preen oil may serve little or no function in Columbiforms (pigeons and doves). We tested that assertion by removing uropygial glands from Rock Doves (Columba livia) and assessing their plumage condition after several months. The results of that experiment showed significant degradation of plumage in the absence of oil. Our results are the first rigorous demonstration that preen oil is important for plumage condition in nonwaterfowl. Omega e tested one possible function of preen oil-that it has insecticidal properties and that reduction in plumage condition on birds without glands is due to an increase in ectoparasites. We tested that hypothesis for feather-feeding lice (Phthiraptera:Ischnocera) using both in vitro and in vivo experiments. Lice raised in an incubator died more rapidly on feathers with preen oil than on feathers without oil, which suggests that preen oil may help combat lice. However, removal of the preen gland from captive birds had no significant effect on louse loads over the course of a four-month experiment. Although the results of our in vivo experiments suggest that preen oil may not be an important defense against lice, further experiments are needed. We also consider the possibility that preen oil may protect birds against other plumage-degrading organisms, such as bacteria and fungi.Original Abstract: La mayoria de las especies de aves tienen una glandula uropigial, la cual produce un aceite que las aves esparcen en su plumaje al acicalarse. Al privarse del aceite uropigial, el plumaje de las aves acuaticas se debilita, haciendose quebradizo. Sin embargo, la importancia de la glandula uropigial en otros grupos de aves no es clara, e investigaciones previas han sugerido que el aceite podria ser poco o nada importante funcionalmente en Columbiformes. Pusimos a prueba esta aseveracion removiendo la glandula uropigial de palomas Columba livia, y evaluando la condicion de su plumaje luego de varios meses. Los resultados de este experimento mostraron una degradacion significativa del plumaje en ausencia del aceite uropigial, lo que constituye la primera demostracion rigurosa de que est