Experimental Test of the Importance of Preen Oil in Rock Doves (Columba Livia)

Abstract

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. We 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.

Use of TLC‐FID and GC‐MS/FID to examine the effects of migratory state, diet and captivity on preen wax composition in White‐throated Sparrows Zonotrichia albicollis

“…There are many hypotheses about its function, including feather maintenance, waterproofing, ultraviolet (UV) protection, antimicrobial action, olfactory camouflage, chemo‐signalling, and sexual attraction (Piersma et al. 1999, Moyer et al. 2003, Haribal et al.…”

Feather‐degrading bacteria, uropygial gland size and feather quality in House SparrowsPasser domesticus

“…Additionally, it has been assumed that UG secretions contain insecticides, which hamper the proliferation of lice (Moyer et al . , Møller et al . ).…”

“…The beneficial effect of preen oil on plumage functionality was demonstrated by the stronger or faster physical feather deterioration in birds that had experimentally blocked or naturally smaller glands (Elder , Jacob & Ziswiler , Moyer et al . , Giraudeau et al . , Moreno‐Rueda ).…”

Effect of Restricted Preen-Gland Access on Maternal Self Maintenance and Reproductive Investment in Mallards

“…These bacteria can influence bird metabolism and immune status, since during maintenance behaviour, birds ingest feather-associated bacteria that are then found in their digestive tracts [29]. Such maintenance behaviour includes preening (or direct application of preen oil to feathers using the bill), which is thought to constitute a first line of defence against parasites [30], [31], [32], [33]. Preen oil (also known as urogygial gland secretions) is composed of a mixture of aliphatic monoester waxes, fatty acids and monohydroxy wax-alcohols [34], and there are at least three modes by which preen oil could influence feather-degrading bacteria (FDB; see [26]).…”