Plumage
Plumage (from
Most birds
Abnormal plumages include a variety of conditions. Albinism, total loss of colour, is rare, but partial loss of colours is more common. Some species are colour polymorphic, having two or more colour variants. A few species have special types of polymorphism, as in the male ruff which has an assortment of different colours around the head and neck in the breeding season only.
Humphrey–Parkes (H–P) moult and plumage terminology
Almost all species of birds
The Humphrey–Parkes terminology requires some attention to detail to name moults and plumages correctly.[8]
Eclipse plumage
Many male ducks have bright, colourful plumage, exhibiting strong sexual dimorphism. However, they moult into a dull plumage after breeding in mid-summer. This drab, female-like appearance is called eclipse plumage. When they shed feathers to go into an eclipse, the ducks become flightless for a short period. Some duck species remain in eclipse for one to three months in the late summer and early fall, while others retain the cryptic plumage until the next spring when they undergo another moult to return to their breeding plumage.
Although mainly found in the Anatidae, a few other species, including related red junglefowl, most fairywrens[a] and some sunbirds also have an eclipse plumage. In the superb and splendid fairywrens, very old males (over about four years) may moult from one nuptial plumage to another[9] whereas in the red-backed and white-winged fairywrens, males do not acquire nuptial plumage until four years of age[10] – well after they become sexually mature and indeed longer than the vast majority of individuals live.[11]
In contrast to the ducks, males of hummingbirds and most
Abnormal plumages
There are hereditary as well as non-hereditary variations in plumage that are rare and termed abnormal or aberrant plumages. Melanism refers to an excess of black or dark colours. Erythromelanism or
The term "dilution" is used for situations where the colour is of a lower intensity overall; it is caused by decreased deposition of pigment in the developing feather, and can thus not occur in structural coloration (i.e., "dilute blue" does not exist); pale structural colors are instead achieved by shifting the peak wavelength at which light is refracted.[12] Dilution regularly occurs in normal plumage (grey, buff, pink and cream colours are usually produced by this process), but may in addition occur as an aberration (e.g., all normally black plumage becoming grey).[13]
In some birds – many
Albinism
Albinism in birds is rare, occurring to any extent in perhaps one in 1800 individuals. It involves loss of colour in all parts including the iris of the eyes, bills, skin, legs, and feet. It is usually the result of a genetic mutation causing the absence of tyrosinase, an enzyme essential for melanin synthesis. Leucism (which includes what used to be termed as "partial albinism") refers to loss of pigments in some or all parts of feathers. A bird that is albino (from the Latin albus, "white") has white feathers in place of coloured ones on some portion of its body. A bird that is naturally white, such as a swan, goose, or egret, is not an albino, nor is a bird that has seasonally alternating white plumage.[17]
Four degrees of albinism have been described. The most common form is termed partial albinism, in which local areas of the bird's body, such as certain feathers, are lacking the pigment melanin. The white areas may be symmetrical, with both sides of the bird showing a similar pattern. In imperfect albinism, the pigment is partially inhibited in the skin, eyes, or feathers, but is not absent from any of them. Incomplete albinism is the complete absence of pigment from the skin, eyes, or feathers, but not all three.[17]
A completely albino bird is the most rare. The eyes in this case are pink or red, because
Albinism has been reported in all orders and in 54 families of North American birds. The American robin and house sparrow led bird species in the incidence of albinism. Albinistic white appears to replace brown pigments more often than red or yellow ones; records suggest a greater incidence in crows, ravens, and hawks than in goldfinches or orioles.[17]
Several kinds of albinism in chickens has been described: A complete albinism controlled by an autosomal recessive gene[19] and two different kinds of partial albinism. One of the partial albinisms is sex-linked[20] and the other is autosomal recessive.[21] A fourth kind of albinism severely reduce pigmentation in the eyes, but only dilutes the pigment in the plumage.[22]
Abnormally white feathers are not always due to albinism. Injury or disease may change their color, including dietary deficiencies or circulatory problems during feather development. Aging may also turn a bird's feathers white.[17]
Hen feathering in cocks
Hen feathering in cocks is a genetically conditioned character in domestic fowl (
Pigmentation conditions
- Albinism, the lack of melanin pigmentation
- Leucism, a condition similar to albinism in animals, characterized by reduced pigmentation in general
- Melanism (or melanosis), unusually dark melanin pigmentation
- Xanthochromism, unusually yellow pigmentation
- Ino budgerigar mutation, the occurrence of this mutation in captive-bred budgerigars
- Axanthism, lack of yellow pigmentation
See also
Notes
a Males of the white-shouldered and emperor fairywrens of New Guinea do not enter an eclipse plumage.
References
- ISBN 9781408130353.
- ^ Foster, Dr. Rory; Smith, Dr. Marty. "Bird Feather Types, Anatomy, Growth, Color, and Molting". Veterinary & Aquatic Services Department. peteducation.com. Archived from the original on 9 February 2017. Retrieved 10 April 2017.
- ^ "Painted Bunting – Introduction – Birds of North America Online". bna.birds.cornell.edu. Archived from the original on 5 August 2016.
- ^ "Galapagos plumology" (PDF). darwinfoundation.org. Charles Darwin Collections Database by the Charles Darwin Foundation. Archived from the original on 17 March 2016. Retrieved 24 April 2015.
- ]
- S2CID 206537426
- (PDF) from the original on 5 March 2016.
- (PDF) from the original on 2 June 2014.
- ISBN 0198546904
- ^ Rowley and Russell; Fairy-Wrens and Grasswrens, pp. 176–177, 181
- ^ See Australian Bird and Bat Banding Studies Archived 12 March 2014 at the Wayback Machine
- ^ Majaron, Hana (December 2013). "Structural coloration" (PDF). mafija.fmf.uni-lj.si.
- ^ Buckley, P.A. 1982. Avian Genetics. In: Petrak, M. (ed.). Diseases of cage and aviary birds, 2nd ed. pp. 21–110. Lea and Febiger, Philadelphia.
- . Retrieved 11 November 2021.
- ^ "Erythrura gouldiae – Gouldian Finch". Australian Government – Department of the Environment and Energy.
- ^ Lindsay L. Farrell, Clemens Küpper, Terry Burke, and David B. Lank (December 2014). "Major Breeding Plumage Color Differences of Male Ruffs (Philomachuspugnax) Are Not Associated With Coding Sequence Variation in the MC1R Gene" (PDF). White Rose Research Online.
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- ^ Grouw, Hein van (2006). "Not every white bird is an albino: sense and nonsense about colour aberrations in birds" (PDF). Dutch Birding. 28: 79–89. Archived (PDF) from the original on 8 August 2017.
- ^ Warren D.C. (1933). "Inheritance of albinism in the domestic fowl". Journal of Heredity. 24: 379–383.
- ^ ^ Mueller, C.D. and Hutt, F.B. 1941 Genetics of the fowl. 12. Sex-linked imperfect albinism, Journal of Heredity. 32, 71–80.
- .
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- JSTOR 1536491.
- PMID 2338489.)
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: CS1 maint: multiple names: authors list (link - PMID 7217085. Archived (PDF) from the original on 13 May 2015.)
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: CS1 maint: multiple names: authors list (link