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Molting
Birds lose and replace most of their feathers at least once yearly; some species
will normally have a partial molt 6 months later. In our area, most species start
their major molt around Valentine’s Day and end it at about the Spring equinox. South
American parrots usually skip the Fall molt but Old World parrots (especially cockatiels)
will sometimes drop feathers a few weeks before the Fall equinox, around Labor Day.
It is important to know if your bird is undergoing normal feather replacement or
has feather loss for other reasons.
Types of Feather Loss
As with different types of molt, there are different types of feather loss.
Feathers can be chewed off at the level of skin, chewed off with the downy aftershaft
left behind, and chewed at the just the tips; leaving a moth-eaten appearance. Other
birds will extract the feathers completely, oftentimes vocalizing painfully during
this process. While other birds simply chew, abnormally preen, or fray their plumage.
Feather loss can also occur from wear and tear, structural damage to the feather
from infectious causes, barbering by cagemates, and cage trauma. Parasites cause
feather breakage or rubbing of the plumage and skin, which also breaks the plumage.
Causes of Feather Loss
To successfully treat a bird with feather loss, it is important to identify
the cause. This often necessitates diagnostic tests to confirm or rule-out disease
syndromes and to confirm health of the patient.
- Viruses- The two most
common viral causes are Psittacine
Beak and Feather Disease
and Polyomavirus. Please see the handouts on these diseases.
- Parasites- Contrary
to public opinion, parasites are rarely a cause for feather loss. Red mites, feather
mites and lice are occasional causes. Brotogerid parakeets often get a Myalges
sp. mite which causes feather loss on their forehead. Giardia protozoa have
been implicated in causing itchy skin but probably do not contribute significantly
to feather loss or damage.
- Bacteria/Fungi- Both
types of organisms are common causes of follicle infection and usually respond well
to medication.
- Nutrition- Malnutrition
is still a cause for feather abnormalities. Fortunately, a thorough history of the
diet and close examination often give telltale clues.
- Barbering-- Cagemates
frequently pick feathers of birds housed with them.
- Behavior- Many factors
contribute to behavioral feather loss: sexual frustration, dominance, boredom, territoriality,
obsessive compulsive behaviors, predator stress from household pets, lack of parental
training for grooming, etc.
- Physical- Organ disease
such as liver damage, kidney failure, tumors, respiratory infection and other infections
contribute to stress-induced feather loss.
- Other Causes- Irritants
such as insect bites, tonics applied to the plumage, ointments, improperly trimmed
flight feathers, etc. can initiate chewing.
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