Nuptial Plumage

Nuptial Plumage, external characteristics that animals acquire during the period of reproduction. Many fish during the spawning period acquire a brighter coloration, which gradually disappears after the breeding period ends. Newts (males) by the time of spawning develop a larger, than at other times, crest-like fin, the belly acquires a brighter coloration, etc. In some reptiles, birds, and mammals, the coloration and shape of certain parts of their skin are somewhat modified by the time of reproduction. In birds that undergo two molts per year, such as ducks, the so-called nuptial plumage is often referred to as the bright plumage that the bird acquires in the fall and in which it appears in the spring during the pairing period. - The mechanics of development of nuptial plumage are not the same in different cases. The bright coloration acquired by fish, newts, frogs, some lizards during the breeding period, and the intensification of pigmentation in certain parts of the body in mammals and birds are connected with the function of the sex glands. In castrated animals, signs of such nuptial plumage do not appear. Of different origin is the so-called nuptial plumage of birds. The bright plumage that ducks acquire in the fall develops independently of the sex glands. A castrated drake during the summer molt acquires a modest plumage, close in type to the plumage of the female, but in the fall it acquires bright plumage, like a normal drake. Many naturalists until recently believed that the development of bright plumage in males of birds that molt twice a year is closely connected with the function of the sex gland. But this assumption is erroneous. Not only the castrated drake, but also the castrated duck, puts on the bright plumage typical of the pairing period.