PAULINE JAMES advises breeders that when buying in new stock, the quality of the plumage holds a wealth of information
WHEN making up pairs of cockatiels it is usual to carefully consider a bird’s colouring or mutation, its size and overall posture. But one of the most important factors to note is the quality of a bird’s plumage, which can reveal a lot about a bird.
Unusual feathering can expose a history of inbreeding and lack of genetic diversity, and other feather disorders can convey that a bird has health issues, or has suffered some sort of trauma as a young chick.
So, when buying in new birds, it is important to be able to recognise all of these conditions, so that disease and genetically inferior birds are not introduced to existing stock.
Birds of a new mutation, and especially the highly desired buttercup yellow birds, are particularly vulnerable to poor feather quality due to the excessive inbreeding that has taken place to produce visuals of this sex-linked mutation, in the brightest and richest yellow possible.
In this process the brightest-coloured parent is often bred back to its brightest-coloured offspring, or worse still two siblings are bred together to increase the intensity of the yellow colouring, and to ensure that visuals are produced in the next generation.
If this practice is repeated for more than one or two generations, which it often is, the diversity of the genes dramatically reduces and all sort of faults begin to start showing up and poor feather quality is one of them.
The structure and texture of the feathering can suffer, and long, thin, soft, silky feathers can be the result. Cockatiels with these unusually long and soft feathers tend to look rather more slender than normal. However, there are always those individuals that go undetected, especially if you only observe them briefly, when they’ve got their wings tightly held to its body.
But once its wings are spread or it is seen in flight, the cockatiel will reveal that it is almost featherless beneath its wings, leaving it extremely vulnerable in the cold.
These “soft” feathers have defective hooklets on the barbules, which serve to lift the edges of the feather slightly, and the bony structures do not interlock properly as they would in hard feathers.
This means that the feathering is unable to do its job properly, notably in providing the bird with high levels of water-proofing and insulating properties. The best way to improve the feathering in the next generation is to pair the bird back to a top-quality normal grey, with good-quality dense feathering, which will inject fresh genes into the mutation.
Avoiding feather cysts
At the other end of the spectrum, there are cockatiels with luxuriant and velvety plumage, in which the feathers are generally shorter and broader than normal. This will show up most clearly in the flight and tail feathers.
Overall, the dense plumage tends to give the cockatiel a plumper and rounder appearance.
But this type of feathering is also abnormal, and if two birds with this sort of feather structure are bred together for consecutive generations, it too can lead to problems, with offspring being particularly vulnerable to developing feather cysts.
These lumps first appear as oval-shaped swellings, which can involve either a single or several feather follicles. Although they may occur anywhere, they are most commonly found in the primary feathers of the wings.
A feather cyst is basically an in-growing feather that is unable to break through the skin, and instead curls round and round inside the follicle. As the feather grows, so the mass enlarges, and a keratin-based pus material accumulates.
Nature and nurture
These two genetically inherited feather types should not be confused feather characteristics that develop after hatching. Changes may take place in a cockatiel’s plumage due to factors brought on by poor conditions or trauma when a chick was being raised, or an on-going health problem due to over-breeding, an inadequate diet, or poor care and housing conditions. Here I explain why cockatiels can suffer from a variety of feather conditions:
■ Broken and ragged feathers can occur after the breeding season, when cockatiels have been confined to a nest-box for a while. But, it is far more likely to happen to birds who have produced more than two clutches, and have been in the nest-box for an abnormally long time.
When parents are forced into an extended breeding season, they miss out on moulting naturally in the autumn, and their body-cycle is thrown off-course; they are then unable to go through a proper moult and replace all their plumage. Cramped housing conditions, and mate trauma can also adversely affect a cockatiel’s plumage.
■ Brittle and fatigued feathers together with dry, scaly skin most often occurs to pet cockatiels housed indoors, and they are often a sign that a cockatiel is kept in conditions that are too dry.
Regular bathing or spraying with tepid water will help. But, feathers in this condition can also be a sign of poor nutrition too, and especially a deficiency of vitamins A and D, and calcium.
■ Stress marks or horizontal lines on feathers are a sign that when the feathers were in the ‘pin’ stage the bird was either ill or under much stress.
It could be that the chick was badly feather-plucked in the nest, or was suffering from internal parasites or red mite at some stage, or even suffered harassment due to over-crowding.
■ Soiled or dirty-looking feathers can be due to damage, or a breakdown in the efficiency of the “powder down” feathers, caused by a health problem. The powdery keratin debris is used by a cockatiel to dust itself down during preening, which serves to cleanse its plumage.
■ Abnormal coloration of feathers can be genetically inherited, linked to a diet deficiency or be due to illness. Viral illnesses and liver problems are the main causes of feather discoloration.
The replacement of a white feather by a golden yellow one often is the first indication of a problem. If it is taken as an early warning and the cockatiel’s health is reinstated immediately, these birds have the ability to restore the white colouring to the feather, without it being moulted-out and replaced.
■ Bronzed and frayed edging to feathers, which appear as dark areas in the plumage, can be the indication of a poor moult. This can be due to illness or poor nutrition. If these signs are accompanied by itchy skin, it could mean that a bird has been used to indoor temperatures, and is struggling to acclimatise to harsh outside temperatures.
A deterioration in the functioning of the thyroid gland or an infestation of internal parasites such as giardia can also cause skin irritation and a poor moult.
■ Psittacine Beak and Feather Syndrome is a viral disease, which is spread by feather dust and dried faeces. Its presence causes progressive feather abnormalities including feather colour changes, stunted feather growth and abnormalities of the beak and claws.
■ French Moult mainly affects newly-fledged chicks. At worst they are virtually featherless, and at best their tail and flight feathers are lost.
The feathers that break off or have fallen out, are malformed and brown, at the tip of the shaft.
Pauline James has been writing for Cage & Aviary Birds since 1994. In her leisure time, Pauline enjoys travelling, and loves watching and photographing parrots in the wild. She lives in Spain.