Most bird species have an organ called the uropygial gland. Located at the base of the spine, on the bird’s croup, this gland secretes a kind of wax that the birds use to polish their feathers. It is thought the wax serves to maintain and protect the feathers, but this hypothesis is still currently debated.
We study this gland in Barn Owls by analyzing how its size varies and the differences in the chemical composition of the wax between individuals. Sometimes the size of the gland and the composition of the wax vary according to the sex of the individual, its age, the period of the year, or even the color of its plumage. In fact, given that the melanin pigments make the plumage rigid, it is possible that the feathers of darker owls need less care, or a different care, than the feathers of lighter owls.
We also look more specifically on the potential protective function of the wax. A bird’s feathers are naturally infested with bacteria that consume keratin, a feather’s primary material. In other words, these bacteria can eat the feathers. We look to understand if the wax produced by the uropygial gland in Barn Owls has antibacterial properties. To do this, we conduct chemical analyses looking for any antibacterial components in the wax.