Question

The fluid used for preening the feathers of pigeon is secreted by
A. Uropygial glands
B. Parathyroid gland
C. Ultimobranchial gland
D. None of the above

Answer 1

Hint: Preening is the act of positioning feathers, cleaning plumage, interlocking feather barbules that have been separated and keeping a check on the ectoparasites with the help of a fluid secreted at the base of the tail and spreading it with the beak.

Complete answer:
Features are an important part of a bird’s appearance and physiology that help it in insulation, waterproofing and helping it in aerodynamic flight making themselves vital for a bird’s survival. Preening can be done individually or with the help of other birds as a social activity and is termed as allopreening.
A bird needs to preen its feathers from time to time because mismanaged feather causes trouble in its flight by interrupting the smooth flight in air and also releasing the preserved body heat. Preening also helps to remove dirt and parasites present in its feathers. Preening involves two types of action – nibbling that is when the bird works on its feather from bottom to the top or stroking with the beak open or closed. Fully grown feathers are basically dead structure and they need to be lubricated from time to time in order of their maintenance and protection. A specialised gland called preen gland is present at the base of the tail of birds which secrete a fluid that is made up of fatty acids, waxes and water. This preen gland is also known as uropygial gland. Bird gathers this fluid with its beaks and spreads it onto its feathers. This preen oil prevents the growth of any kind of bacteria or parasites like lice and fungi on the bird’s feathers.
Uropygial gland is a sebaceous gland having a bilobed structure and is present in almost all birds. It varies in shape and size from species to species. It is a holocrine gland means its secretions are produced in the cytoplasm of the cell and released by the rupture of the plasma membrane.

So the answer for this question is Option A – Uropygial gland.
Parathyroid and ultimobranchial glands are involved in the calcium mechanism in birds.

Note:
Preen oil is secreted through the dorsal surface of the skin by a grease nipple like structure called a nub or papilla. The oil is made up of aliphatic monoester waxes formed by a mixture of fatty acids and monohydroxy wax alcohols.