PLUCKING IN PARROTS
By Dr Colin Walker BSc, BVSc, MRCVS, MACVSc
Feather plucking is one of the most common and yet one
of the most complex and at times frustrating conditions that avian
veterinarians are presented with.
The first step always in dealing with a behavioural problem such
as feather plucking (the other two common problems being screaming
and biting) is to make sure that it doesn’t have its roots
in an underlying health problem. Feather plucking is a symptom
of something else wrong with the bird. The only chance of a successful
outcome is to identify and correct what is behind the behaviour.
Every feather plucker or feather chewer has a reason for exhibiting
the behaviour. Remember, feather plucking is a symptom and not
a disease in itself.
And so, what possible health problems are going through an avian
vet’s mind when he is initially presented with a feather-plucking
parrot for examination and, indeed, what sort of diagnostic tests
are at his disposal?
Primary feather follicle irritation
Feather follicles that are itchy or irritated attract the bird’s
attention. In its attempt to make itself comfortable, the bird
may chew or pick at the feather. Possible causes include an infection
associated with mites, bacteria, fungi or a virus. Some species
of mite live deep in the feather follicle, wedged between the outer
wall of the feather and the lining of the feather follicle. A simple
in-aviary test that might indicate the presence of mites is to
gently roll a damaged feather out of its follicle. If mites are
present, there may be a collar of dry dandruff-like material around
the feather. A vet can scrape this material onto a drop of oil
on a microscope slide and examine it. Examination can reveal adult
mites, nymphs and also eggs. A feather with a healthy follicle
is often harder to remove and the section of feather below the
skin is clean and shiny. Generalized bacterial infection associated
with bacteria such as Staphylococcus can be intensely itchy, while
fungi (such as Mucor sp. and Rhizopus sp.) have been associated
with itchiness in pigeons as well as parrots. Veterinarians can
take skin scrapings and squash feather contents onto slides for
microscopic examination. Sometimes, special stains can aid in diagnosis.
Feather and skin samples can also be cultured for bacteria and
fungus. Both Polyoma virus (associated amongst other things with ‘French
Moult’ in budgies) and Circo virus (the agent of PBFD in
cockatoos and other birds) can inflame the feather follicle, leading
to the growth of abnormal feathers and variable degrees of irritation.
These viruses are tested for usually in blood and feather samples
where either evidence of the virus itself or antibody to the virus
is detected. Interestingly, itchy birds that may appear quite normal
sometimes test positive for Circo virus, which means that even
though no obvious feather damage is visible, the virus should not
The jury is still out on the importance of allergies in itchy birds.
What we do know is that we see clinical disease and microscopic
lesions associated with allergies in birds that scratch and feather
pick. Also, there is a significant difference in the skin testing
results between normal and itchy birds. Suggested allergens include
Aspergillis sp. (a fungus that grows on organic material such
as straw, etc in damp conditions) and sunflower seeds.
Many things found in households that are quite innocuous to humans
have been associated with itchy skin in birds. Vapourised cooking
oils, alcohol-based sprays and cigarette smoke can all irritate
the skin. The low humidity created by central heating is also
particularly irritant to rainforest parrots, such as macaws,
which have evolved to do well in more humid environments.
Birds don’t have hands but, in the same way that we might
rub a sore area to try and make it feel better, birds will pick
and chew over an area that is sore. And so, chewing of a localized
area may indicate pain or discomfort in that area. A common syndrome
here occurs in cockatiels that chew and damage the feathers over
their body generally but often particularly over their abdomen.
Microscopic examination of these birds’ droppings sometimes
reveals a Giardia (a flagellate) infection. Treatment of the Giardia
often leads to a resolution of the feather picking. The exact mechanism
here is not known but it is thought that either a toxin produced
by the Giardia or alternately direct discomfort caused by the organism
in the bowel leads to the self-trauma. Chlamydophila infection
has also been associated with feather chewing, either due to primary
skin changes or internal pain associated with the disease. Liver
disease can lead to the deposition of irritant bile salts in the
skin. Poorly healed fractures have also been associated with self-trauma.
Screening X-rays, blood profiles, together with microscopic examination
and cultures of throat swabs and droppings, as well as specific
tests for Chlamydophila are all used to gather information.
Poor diets can not only lead to poor quality feathers and dry flaky
skin but can also make the skin more vulnerable to secondary
infection. Both scenarios result in unhealthy skin that becomes
itchy. The diet of any bird with poor quality feathers should
always be reviewed. This appears particularly so in Eclectus
parrots and it is surprising how many of these birds respond
simply to dietary improvement. Vitamin A, in particular, is the
nutrient required for healthy skin and mucous membranes. Vitamin
A deficiency should always be suspected in birds whose diet is
based on dry seed.
Heavy metal poisoning, most commonly associated with inadvertent
lead or zinc ingestion through chewing new wire or other metal
objects, can lead to behavioural changes (together with other
problems) that may manifest as compulsive feather chewing.
Tumours, feather cysts, xanthomas and non-healing wounds can all
draw a bird’s attention to a particular site, leading to
Some birds prior to breeding, e.g. some cockatoos, will pluck their
feathers to line nesting logs.
Poor feathering and feather loss can occur secondary to some hormonal
problems, such as hyperthyroidism (increased function of the
thyroid gland) and Addison’s disease (decreased formation
of corticosterone by the adrenal gland). Although not a direct
cause of feather picking, they may predispose the bird to secondary
problems and cause low-grade itchiness.
Diagnosis of a medical cause behind feather picking can be time
consuming and at times costly. As veterinarians, we often face
the challenge of providing an accurate diagnosis within given financial
constraints. Veterinarians endeavor to get to the bottom of the
problem without spending client’s money on tests that are
unnecessary but at the same time it is important that the bird’s
health is not put at risk through an unidentified problem. Usually,
however the combination of a concerned bird owner and keen avian
vet will identify any medical problem present.
Physical v. psychological
Self-mutilation can be either a physical or psychological problem.
If the bird’s clinical examination and diagnostic testing
fail to identify a health problem, then through a diagnosis of
exclusion a psychological problem becomes more likely.
Parrots are naturally active, intelligent birds that with insufficient
input to their sensory pathways simply go ‘stir crazy’.
In the same way that a bored lonely working dog confined to a suburban
yard will start to exhibit abnormal behaviour, such as barking
excessively, being aggressive or destroying objects, parrots will
release the same frustrations through mutilating themselves.
In the wild, parrots spend a long time with their parents and
in some species (e.g. the galah) crèche groups are formed.
This social structure tends to educate the growing birds and reinforce
correct behaviour. Birds raised in isolation from a young age are
vulnerable to developing a range of aberrant behaviours, including
feather plucking. The identification and management of psychological
feather plucking is involved and challenging and will be only briefly
touched on here.
Psychological self-mutilation usually occurs either as a result
of boredom, sexual frustration or anxiety.
Free-flying parrots live in a three-dimensional world full of colour
and activity. The parrot owner must mimic this as closely as
possible through enriching the bird’s environment. The
type of cage, cage location and the provision of interesting
food and toys are all relevant here.
Many free-roaming parrots travel with their mate in small roving
bands. They therefore have a natural need for companionship.
In captivity, pet birds will often develop what they perceive
as a ‘mate’ relationship with their primary carer.
This is obviously inappropriate as no human can fulfill such
a role. Fostering such a relationship leads to a situation of
unrequited love and simply serves to further the bird’s
mental confusion and frustration. The appropriate role for an
owner to adopt is that of a friend not a mate. The pet bird should
view its primary carer as a benevolent leader. Interestingly,
it is thought that the fatty seeds provided in some commercial
diets may contain oestrogen precursors and may in some way act
as aphrodisiacs, further exacerbating the situation.
Overcrowding, close housing to a non-compatible species excessive
noise or disturbance, etc, etc, can all be sources of anxiety.
Evaluation needs a careful review of a bird’s management
No matter what the cause of feather plucking, the earlier it
is identified and corrected the better is the chance of a successful
outcome. As always, your local avian veterinarian is the best person
to consult for advice.