Pet Health Articles

Molting in Birds

Feathers are a truly phenomenal, complex and beautiful structure. Like hair or fur on mammals, they have many very important functions. Feathers insulate to maintain body temperature and protect birds from the elements (cold, heat, weather, wet, etc) Feathers play an important role in aerodynamics and flying. Feathers provide camouflage, display during courtship, display territoriality and sexual dimorphism (differences between the sexes) in many species. Feathers can be used as nesting material.

 

What is moulting?moulting-1

Each feather occupies a single feather follicle. Unlike hair, feathers do NOT continually grow; once a bird's feathers have grown in, they cannot be repaired if they become worn or damaged. As long as a feather occupies a feather follicle, it will not be replaced. The feather needs to be removed or fall out to stimulate new feather growth. Therefore, to keep itself in fine feather, a bird needs to moult each year to get rid of old or damaged feathers. Moulting is required to renew a bird's plumage and keep it in top condition. This will facilitate efficient flight, temperature regulation, protection and is often associated with reproduction (courtship display).

 

When do birds moult?

In the wild, moulting is usually related to the change of seasons or the changing day length. Change of season or day light hours stimulates moulting, migrating and breeding. Other factors influencing moulting include temperature, nutrition, general health, and reproductive state. Most wild birds will moult heavily in the spring and fall; between seasons, they may continuously replace old or lost feathers. Over a one-year period, each and every feather will normally have been replaced with a new one. Moulting occurs in a gradual, bilateral and symmetrical sequence so that the bird is not left bald and unable to fly.

"Moulting occurs in a gradual, bilateral and symmetrical sequence so that the bird is not left bald and unable to fly."

In captivity, birds can become unconsciously "confused" as we have artificial light sources that we usually turn off and on at our convenience. We do not have seasonal light and daylight length fluctuations that would emulate "season" in our homes.  We humans may sleep in one day and not the next. We may go to bed early or shut the lights out after the 11:00 p.m. news has finished. This human manipulation of environmental stimulus may lead to irregular, incomplete, long or short moults; in some cases, moulting may occur continuously or may only occur every couple of years.

 

Does my bird need anything special during a moult?

"Building lots of new feathers (as in a heavy moult) can be very stressful and taxing on a bird's bodily resources."

During a moult, nutrition is of utmost importance. Nutrition does not have to be better in times of moulting; instead, it should be optimal all year round. There is an increased demand for proteins, calcium and iron. Building a new feather requires a lot of energy and plenty of good quality nutrients. Building lots of new feathers (as in a heavy moult) can be very stressful and taxing on a bird's bodily resources. Some birds become less active, quiet, or stop laying eggs; birds like canaries may stop singing while moulting and growing in so many new feathers. Birds may become more prone to health problems during these stressful times as the immune system is also under stress.

If your bird is having irregular moults, abnormal feather growth or you are just not sure if its moulting patterns are normal, then have the bird examined by a veterinarian familiar with birds.

Rick Axelson, DVM
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