Feather-plucking, sometimes termed feather-picking, feather damaging behaviour or pterotillomania, is a maladaptive, behavioural disorder commonly seen in captive birds that chew, bite or pluck their own feathers with their beak, resulting in damage to the feathers and occasionally the skin. It is especially common among
parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoi ...
s (order ''Psittaciformes''), with an estimated 10% of captive parrots exhibiting the disorder. The areas of the body that are mainly pecked or plucked are the more accessible regions such as the neck, chest, flank, inner thigh and
ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
wing area.
Contour Contour may refer to: * Contour (linguistics), a phonetic sound * Pitch contour * Contour (camera system), a 3D digital camera system * Contour, the KDE Plasma 4 interface for tablet devices * Contour line, a curve along which the function ha ...
down feathers The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and ...
are generally identified as the main target, although in some cases, tail and flight feathers are affected. Although feather-plucking shares characteristics with feather pecking commonly seen in commercial poultry, the two behaviours are currently considered to be distinct as in the latter, the birds peck at and pull out the feathers of other individuals. Feather-plucking has characteristics that are similar to
trichotillomania Trichotillomania (TTM), also known as hair-pulling disorder or compulsive hair pulling, is a mental disorder characterized by a long-term urge that results in the pulling out of one's own hair. A brief positive feeling may occur as hair is remov ...
, an impulse control disorder in humans, and hair-pulling which has been reported in mice, guinea pigs, rabbits, sheep and muskox, dogs and cats, leading to suggestions for a
comparative psychology Comparative psychology refers to the scientific study of the behavior and mental processes of non-human animals, especially as these relate to the phylogenetic history, adaptive significance, and development of behavior. Research in this area addr ...
approach to alleviating these problems.


Feather-plucking is generally regarded as a multifactorial disorder, although three main aspects of bird keeping may be related to the problem: (1) cage size often restricts the bird's movements; (2) cage design and barrenness of the environment often do not provide sufficient behavioural opportunities to meet the bird's sensitivity, intelligence and behavioural needs; and (3) solitary housing, which fails to meet the high social needs of the bird.

Social and environmental factors

Early experience

Feather-plucking is often attributed to a variety of social causes that may include poor socialisation or absence of parents during the rearing period and because of this, the individual subsequently expressing the disorder fails to learn appropriate
preening Preening is a found in birds that involves the use of the beak to position feathers, interlock feather that have become separated, clean plumage, and keep ectoparasites in check. Feathers contribute significantly to a bird's insulation, water ...
behaviour. Several studies have focused on the importance of rearing methods (wild-caught, parent-raised, hand-reared).


In captivity, pet birds are often kept isolated from conspecifics whereas in the wild they would form stable, sometimes large, flocks. These birds may not deal well with a solitary lifestyle. Deprivation of a social or sexual partner may lead to 'separation anxiety', ‘loneliness’, ‘boredom’, sexual ‘frustration’ and ‘attention-seeking’ behaviour. These factors may all contribute to feather-plucking, although no empirical studies have been performed to test these ideas.

Barren environment

Increasing environmental complexity can reduce feather-plucking, however, other studies have only managed to stabilise existing plumage problems.

Re-directed foraging behaviour

Increasing foraging opportunities can markedly reduce feather-plucking. This has many similarities with the redirected foraging behaviour hypothesis proposed for feather pecking in commercial poultry. Birds in captivity are usually given energy-dense, readily available food that is consumed rapidly, whereas in the wild they would have to spend many hours foraging to find this. It is considered that a combination of a barren environment and the 'excess' foraging time available is then spent redirecting foraging to feathers of other individuals. When 18 feather-plucking grey parrots (''Psittacus erithacus'') were provided with food in pipe feeders rather than bowls, their foraging time significantly increased by 73 minutes each day and their plumage improved noticeably within one month.


Feather-plucking has also been interpreted as a coping strategy for negative affective states e.g. stress, loneliness, boredom, induced by inappropriate social or environmental factors. Findings in favour of the stress hypothesis include a study in which distinctive room position affected occurrence of the disorder. Orange-winged amazon parrots (''Amazona amazonica'') that were housed in proximity and direct line of sight to the door showed significantly more feather-plucking compared to individuals housed further away from the door, indicating presence of stressors as a causal factor. In addition, parrots that feather-pluck have been found to have higher levels of
corticosterone Corticosterone, also known as 17-deoxycortisol and 11β,21-dihydroxyprogesterone, is a 21-carbon steroid hormone of the corticosteroid type produced in the cortex of the adrenal glands. It is of minor importance in humans, except in the very rare ...
, a hormone secreted by many animals when they are exposed to chronic stress. It has also been suggested that long day-lengths can cause feather-plucking; presumably this could relate to birds becoming overly tired and therefore stressed.

Medical and physical factors

Many medical causes underlying the development of feather-plucking have been proposed including allergies (contact/inhalation/food), endoparasites, ectoparasites, skin irritation (e.g. by toxic substances, low humidity levels), skin desiccation,
hypothyroidism Hypothyroidism (also called ''underactive thyroid'', ''low thyroid'' or ''hypothyreosis'') is a disorder of the endocrine system in which the thyroid gland does not produce enough thyroid hormone. It can cause a number of symptoms, such as p ...
, obesity, pain, reproductive disease, systemic illness (in particular liver and renal disease),
hypocalcemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6  mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 m ...
, psittacine beak and feather disease (PBFD), proventricular dilatation syndrome,
colic Colic or cholic () is a form of pain that starts and stops abruptly. It occurs due to muscular contractions of a hollow tube (small and large intestine, gall bladder, ureter, etc.) in an attempt to relieve an obstruction by forcing content out. ...
, giardiasis, psittacosis, airsacculitis, heavy metal toxicosis, bacterial or fungal folliculitis, genetic feather abnormalities, nutritional deficiencies (in particular vitamin A) and dietary imbalances, and neoplasia. For many of the above-mentioned factors, a causative relationship or correlation has not been established and may therefore merely be the result of coincidental findings. Approximately 50% of parrots exhibiting feather damaging behaviour have been diagnosed as having inflammatory skin disease based on paired skin and feather biopsies. The birds try to relieve itching by grooming their feathers, but this often leads to over-grooming and eventually feather-plucking.

Neurobiological factors

Little is currently known on brain dysfunction in feather-plucking. However, it may be hypothesized that abnormal brain function is involved, especially in those cases that appear sensitive to treatment with behavioural intervention and environmental changes. Psychotropic therapy for birds has been suggested as treatment for feather-plucking although responses seem variable.

Genetic factors

In orange-winged amazon parrots, a
heritability Heritability is a statistic used in the fields of breeding and genetics that estimates the degree of ''variation'' in a phenotypic trait in a population that is due to genetic variation between individuals in that population. The concept of he ...
estimate of 1.14 ± 0.27 was found for feather-plucking, indicating that a genetic basis exists. This study, however, only involved analysis of full siblings and a small number of birds, explaining the heritability value of greater than 1. Quantitative trait loci (QTL) analysis could provide more insight in possible genetic markers that are involved in feather-plucking.


Veterinary treatment or an improved and more stimulating environment may help birds suffering from feather-plucking. Organic bitter sprays are sold in pet stores to discourage plucking, especially of newly grown feathers, although this may make general beak-based grooming difficult for the animal. This is not recommended since it does not address the real reason why the bird is picking feathers. Likewise, physical items such as collars or vests, which are commercially available or may be improvised by the parrot's owner from items such as
pipe insulation Pipe Insulation is thermal or acoustic insulation used on pipework. Applications Condensation control Where pipes operate at below-ambient temperatures, the potential exists for water vapour to condense on the pipe surface. Moisture is known ...
tubes (placed around the neck) or socks (cut into a vest which the bird is made to wear) may prevent the bird from plucking by providing a barrier which makes the act more difficult, but does not deal with the underlying cause of the feather-plucking. Studies have shown that administration of
haloperidol Haloperidol, sold under the brand name Haldol among others, is a typical antipsychotic medication. Haloperidol is used in the treatment of schizophrenia, tics in Tourette syndrome, mania in bipolar disorder, delirium, agitation, acute psychosi ...
to affected birds will cause a long-term reduction in obsessive feather-plucking, however the birds always relapsed as soon as the medication was withdrawn.
Clomipramine Clomipramine, sold under the brand name Anafranil among others, is a tricyclic antidepressant (TCA). It is used for the treatment of obsessive–compulsive disorder, panic disorder, major depressive disorder, and chronic pain. It may increase th ...
is also linked to minor long-term improvement for the condition, although it is not generally as effective as haloperidol. Administration of
fluoxetine Fluoxetine, sold under the brand names Prozac and Sarafem, among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used for the treatment of major depressive disorder, obsessive–compulsive disorde ...
is also known to reduce feather-plucking activity but only for very short periods of time, with the birds generally relapsing after several weeks of therapy and requiring a continually increasing dose of the medication. Use of fluoxetine for this condition is also linked to major relapse of feather-plucking when the medication is withdrawn, and it is known to cause severe psychological side-effects in certain birds.

See also

* Abnormal behaviour of birds in captivity * Animal psychopathology *
Comparative psychology Comparative psychology refers to the scientific study of the behavior and mental processes of non-human animals, especially as these relate to the phylogenetic history, adaptive significance, and development of behavior. Research in this area addr ...
* Stereotypy * List of abnormal behaviours in animals


External links

Feather Plucking in African Grey Parrots
* ttp://ricobird.wordpress.com/ Ricobird: A Solution for Self-Mutilation and Feather Picking {{Authority control Abnormal behaviour in animals Bird diseases Feathers Bird behavior Self-harm