Angel Wing
Encyclopedia
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
that affects waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
, primarily geese
Goose
The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....
and duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s, in which the last joint of the wing is twisted with the wing feathers pointing out laterally, instead of lying against the body. Males develop it more than females.
The disease manifests as an incurable anatomical condition which is acquired in young birds. Due to a high-calorie
Calorie
The calorie is a pre-SI metric unit of energy. It was first defined by Nicolas Clément in 1824 as a unit of heat, entering French and English dictionaries between 1841 and 1867. In most fields its use is archaic, having been replaced by the SI unit of energy, the joule...
diet, especially one high in protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s and/or low in vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
, vitamin E
Vitamin E
Vitamin E is used to refer to a group of fat-soluble compounds that include both tocopherols and tocotrienols. There are many different forms of vitamin E, of which γ-tocopherol is the most common in the North American diet. γ-Tocopherol can be found in corn oil, soybean oil, margarine and dressings...
and manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
, one or both carpus
Carpus
In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers , whereas those of the metacarpus do. The corresponding part of the foot is the tarsus...
(wrist) joints are retarded in their development relative to the rest of the wing; for reasons unknown, if only one wing is affected it is usually the left one. The result is a wrist which is twisted outwards and unable to perform its usual function. Angel wing symptoms include stripped remiges (flight feathers) in the wrist area, or remiges protruding from wings at odd angles. In extreme cases, the stripped feathers may resemble sickly blue straw protruding from wings. In adult birds the disease is incurable and usually leads to an early death as affected birds are rendered effectively or totally flightless. In young birds wrapping the wing and binding it against the bird's flank, together with feeding the bird a more natural diet, can reverse the damage.
The only wild waterfowl populations known to be affected are those fed by man. In Sweden, ten different park populations of Canada geese produced angel wing. The following year one flock was not fed any artificial feed and there were no angel wing goslings produced.
There are currently two basic theories concerning the cause of Angel Wing:
- The first involves too much protein and the second involves too many sugars . Angel Wing is not generally observed in waterfowl not residing near humans, and the disease can often be observed in areas where geese or ducks are excessively fed breadBreadBread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...
. To prevent Angel Wing, waterfowl should not be fed bread, popcorn or other human foodstuffs . Duck seed is an alternative for duck feeders. - The second theory is that the cause could be genetic, as the same breeding pair can produce several Angel Wing chicks or cygnets over many broods.
As little research has been done on this, it is currently impossible to favour one theory over the other.