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Feathers and Molting
October 14, 2013

I was taking my walk this past Thursday evening, when a young girl brought her puppy up to me to see/pet.

Like most pups, he was skiddish and started to bark at me in that nervous way little breeds do.

Her brother walked up and said "He doesn't like old people.'


I tried to explain the pup was nervous and afraid, then I walked away chuckling.

Afraid of old people...........................

Out of the mouth of babes.

Real Autumn weather sets in this week.

I must say, the past two weeks were as good as it can get (weather wise), here in Michigan.

The hummingbird feeders came down this past week.

Cleaned and put away till Late April or early May.

Every year around here, we have at least one late nesting Northern cardinals.

This year is no exception.

For the past few days, right around dusk (after sunset), Papa and fledged cardinal show up.

The color of the bill and feet show it is a very young bird.

The color patches and dark mask around the bill suggest this is a young male that also has to molt into adult colors.

Isn't "Nature Grand"?

(A picture of daddy feeding baby is below.)

Just like that, fledged and molting.

And that is the segue into today's letter on molting.



You may notice your birds are sporting a new look these days.

Healthy feathers offer protection, by keeping a bird dry.

They help to regulate temperatures by cooling and warming a bird.

Healthy feathers aid in flight.

Indeed, each feather can be individually maneuvered.

Healthy feathers aid in finding a mate.

What else can a feather do?

A bird's very life relies on its feathers.

Take note:

The young fledged cardinal is already molting to his sub adult plumage, even as daddy feeds and cares for him.

Notice the dark mask already beginning to show, the lack of a crown, and the still fledged gray colors of his bill and legs.

(Old Turkey Feathers.)

The replacement of all or part of the feathers is called a molt or Moult.

I will use molt in this letter.

A feather is a "dead" structure, somewhat like your hair or nails, except your hair and nails continue to grow.

We can cut off split ends and trim up and manicure cracked nails.

Since feathers cannot heal themselves when damaged or keep growing like a finger nail or hair, they have to be completely replaced.

Damaged feathers are replaced during a molt.

When a individual feather that has been lost, it completely is replaced immediately.

The hardness of a feather is caused by the formation of the protein keratin.

Molts produce feathers that match the age and sex of the bird, and sometimes the season.

Molting, like migration occurs mostly in response to a mixture of hormonal changes brought about by seasonal changes (typically length of day).

The entire process is complex and many questions remain regarding how the process takes place and often Scientific equations are used to show body weight, energy used and so on.

No need to bore you with that
stuff, besides.............

I don't understand all of it myself.

A basic understanding of molting patterns can, however, be a useful aid in identifying many species and in determining their age.

(Same Turkey Feathers Close up, used and abused.)

In temperate zones, cue for molt initiation is day length, which has an effect on the hormone levels that ultimately control molt progression (and other things).

What most people don't realize is this......

Molting is very costly, as it consumes energy and can cost a bird in its ability to fly (and its life).

For example:

Canada Geese molt occurs between mid-June through August.

The 8-10 week flightless period when Canada Geese shed their outer wing feathers and regrow new ones.

Most birds are able to resume flight by mid-August.

During this molting period geese will gather on ponds or lakes since they provide a safe resting place and security from predators.

These large groups of “flightless" geese are grounded and dependent on available food sources which often get overgrazed and subsequently they produce excess waste and destroy turf and other vegetation.

Geese without young will sometimes travel hundreds of miles to the security of favored molting areas in the north.

These “molt migrations” account for the disappearance of local goose flocks in early June.

I digress.

The bird replaces 25 – 40 percent of its dry mass, drawing on protein and energy reserves to make and grow new feathers and to offset the effects of reduced insulation and flight ability.

Because it is so costly, molt is often interrupted in order to begin breeding activities or for migration.

Because it is so costly, molt is often interrupted in order to begin breeding activities or for migration.

Many birds go through a quick series of plumages in their first months of life, and then cycle between a basic, or winter, plumage worn for most of the year and an alternate, or breeding, plumage worn only during spring and summer.

This may bore you to tears, but here is a plumage sequence and molt.

Many bird watchers (us backyard birders) are used to thinking of the often brighter summer plumage as a bird's main look, so this system may confuse you at first.

Birds that have a breeding and non breeding plumage are usually in the non breeding plumage for a longer period of time from late summer or early fall to early spring.

Often following a full molt.

Prebasic molt:

Prebasic molt usually takes place on the breeding grounds, but may take place during fall migration or on the winter grounds.

In adults, the prebasic molt is usually complete and results in the adult basic plumage.

In first or hatch-year birds, it is referred to as the first prebasic molt and results in the first prebasic plumage.

The second prebasic molt is complete, and results in the second basic plumage, which is generally the adult definitive plumage (adult basic plumage).

Many birds don't reach their true adult colors until the second or third basic molt (longer for some).

You may notice this with Goldfinches, or other bright colored birds.

One male is clearly more colorful than the ones next to him, it could be diet, but most likely the age of the birds.

This may or may not deter mating, depending on species, locations and other factors.

Basic plumage:

The basic plumage is generally worn during fall, winter, and early spring.

In first or hatch-year birds, it is called the first basic plumage and is not the definitive (final adult) plumage, since the feathers of the wings and tail are generally not replaced in the first prebasic molt.

These feathers retain qualities of the juvenile plumage, making birds in their first basic plumage generally distinguishable from those in their adult basic plumage (a very common sight with Red-winged blackbirds).

The adult basic plumage is the definitive plumage to which adults return after every breeding season.

Juvenile passerines generally achieve the adult basic plumage by their second basic plumage.

Some non passerines (gulls, eagles) and some passerines (orioles, manakins) take more than 2 years to reach the definitive plumage.

Prealternate molt:

In some birds, the prebasic molt is the only molt that occurs annually; thus, breeding occurs in the basic plumage for these species (American Robin and the woodpeckers).

In most passerines, the prealternate molt causes the replacement of the basic plumage with the alternate plumage during winter or spring.

In hatch-year birds, it is called the first prealternate molt and
results in the first alternate plumage.

In adults, it is referred to as the adult prealternate molt and results in the adult prealternate plumage.

Prealternate molts are generally partial,though the extent of the prealternate molt varies substantially among species and between sexes.

Are you bored yet?

Alternate plumage:

In adults, the alternate plumage is referred to as the adult alternate plumage, whereas in hatch-year birds, it is the first alternate plumage.

In many passerines, the adult alternate plumages of males differ from their adult basic plumages, whereas in females, both plumages are similar.

Birds in their first alternate plumage are generally duller than those in the adult alternate plumage.

There are two kinds of molts with different degrees of feather replacement.

In a complete molt all feathers are replaced.

In a partial molt only some feathers are replaced.

It takes a lot of energy to build new feathers.

Molting is, therefore, often timed to coincide with periods of less strenuous demands, such as after nesting or before migration.

Still, some birds molt during migration.

Some birds molt after migration.

Some birds start and stop during migration.

There is no definite time for molting.

Molting, like migration takes place all through the calendar year.

Indeed, it may take a Bald eagle a few years to finish a single molt cycle, only to start all over again .

It take 5 years and a series of molts For a Bald eagle to reach adult plumage.

How often do birds molt?

This varies by species, but almost all birds fall into one of the following three categories.

Many species have one complete molt per year.

These include:

Chickadees, Flycatchers, Hawks, Hummingbirds, Jays, Swallows, Thrushes, Vireos, Woodpeckers and Owls.

Some species have a complete molt after nesting, molting into their basic plumage.

These species then have a prenuptial molt of body feathers that results in their bright breeding plumage.

Species with this molt pattern include: Buntings, Tanagers, Warblers and American Goldfinches.

While females of these species usually look very similar on a year-round basis, they do go through a partial prenuptial molt and can be described as being in alternate plumage for part of the year.

The male American goldfinch undergoes a complete molt in the late summer/fall that results in a drab olive green to dull brownish/yellow bird with typical goldfinch wings.

In spring the male American goldfinch undergoes a partial molt, including the body feathers. The new body feathers are a brilliant rich canary yellow color.

Some species undergo two complete molts each year.

Bobolinks for example, go through two complete molts.

After breeding all the feathers are molted and the male looks very much like the female.

Often confusing bird watchers.

For spring or mating, he goes through another complete molt to get his beautiful black and white 'Bobolink' colors once again.

Molting Patterns Vary By:


Individual birds of the same species.

From year-to-year.

By individual feathers.

Development of Feathers and Follicles:

Most adult birds are covered with feathers except on the beak, eyes, and feet.

The contour feathers are arranged in rows and groups of follicles.

A follicle ordinarily produces a series of
feathers during a bird's life.

If the bird molts, the new feather pushes out the old one.

If a feather is lost some other way, the follicle replaces it immediately or at the next molt, depending on the time of the next molt, the health of the bird, its reproductive state, etc.

A new feather can be grown in two weeks but it depends on the species of bird, time of year, and type of feather.

While American goldfinches molt right before your eyes, Northern Cardinals seem to almost disappear from our yards when they are in molt.

The number of feathers is relatively constant within a species although they tend to have more feathers in the winter than in the summer.

Smaller birds tend to have more feathers per area than larger birds although fewer feathers total.

A Ruby-Throated Hummingbird has roughly 940 feathers,

A Tundra Swan has as many as 25,000 feathers.,

American Goldfinches change all their feathers in the fall and just the body feathers in the spring where the male becomes a bright yellow – the better to attract mates.

Coastal Lesser Goldfinches perform a full molt in the fall and some perform a body molt in the spring.

Interior Lesser Goldfinches perform a full molt twice a year: spring and fall.

Hummingbirds start their molt during migration as do Barn swallows and the swallow family in general

Hummers often have that late brood, so they begin migration and molt around the same time.

Sandhill cranes molt during and after migration.

Common loons molt after migration because of their weight and build, they need every feather possible for flight.

Water fowl go through a molt right after nesting, rendering them flightless for a period of time.

Often ducks, geese and swans will hideout in swamps, marshes or even in open water where they are somewhat protected.

Male ducks often look like females until they go through still another molt in the fall that brings back the male colors (going on now).

I'm getting worn out just thinking of it all.

There really is no easy time in a bird's life.

Some species, somewhere is molting.

Protein is essential for growing strong feathers.

Fats are essential for feather coloration.

Every molting bird needs extra proteins to grow strong feathers for proper flight and effective insulation.

They need extra fats for energy to grow feathers and provide proper coloration to best attract a mate.

Feathers are 91% protein,( primarily keratins) 1.3% fat and 7.7% water.

A bird’s feathers contain 25% of the total protein found within its entire body.

It takes extra energy to grow feathers and also the right building blocks to grow them.

The main ingredients in growing feathers are amino acids (protein) and lipids (fats).

Birds will eat more of their daily diet and / or seek out foods high in protein and fat to satisfy both the extra energy requirements and the needed building blocks.

Lipids are substances such as a fat, oil or wax (usually from tree fruits).

Dietary lipids supply energy, essential fatty acids and pigments for birds.

Like pigment dyes that are used to color our clothes, colors in feathers come from different pigments found in lipids.

Red, orange, and yellows to violet colors = Carotenoid pigments

Black, brown, gray and related tints = Melanin and porphyrin pigments

Blue and white colors = Not created by pigments but by reflections of light off the structural elements of a feather

Greens = Carotenoid and melanin pigments combined with structural feather elements

In many bird species, carotenoids are required for breeding success...poorly colored birds are less likely to breed.

Carotenoids help communicate reproductive fitness to prospective mates by providing a vibrant and bright plumage.

A sign of being successful at obtaining both a sufficient quality and quantity of food.

The more color and more brightly colored a male House Finch the greater the likelihood of attracting a mate.

A male Red-winged Blackbird’s dominance depends on his bright red shoulder epaulettes being bigger than another male’s.

The larger the red epaulet patch, the better he can defend a territory and attract multiple mates.

A diet low in proteins and fats may cause feathers to be improperly colored or form defectively such as being frayed or curved.

Native plants help to provide the proper needs (this is why I preach for you to plant native).

If their colors are duller birds may have trouble attracting a mate.

If the feathers are defective, it could seriously hinder their flying or insulation abilities.

Birds will eat more of their daily diet and/or seek out foods high in protein and fat to satisfy the extra energy requirements and the needed building blocks to grow feathers.

Here is some of the nutritional information on foods:

Peanuts - 90 protein calories

Nyjer - 84 protein calories

Choice Blend - 71 protein calories

Sunflower chips - 70 protein calories

No-mess Blend - 68 protein calories

Supreme Blend - 68 protein calories (per 100 grams, 3.5 oz. or about 1/2 cup)

Sunflower Chips - 429 fat calories

Peanuts - 412 fat calories

No-mess Blend - 351 fat calories

Choice Blend - 350 fat calories

Nyjer - 342 fat calories

Supreme Blend - 332 fat calories (per 100 grams, 3.5 oz. or about 1/2 cup)

Offer your birds what they want and need.

As you can see by the above list, Peanuts, sunflower and Nyjer are high on every list.

I will add suets to that list as well.

Offer what birds want and need and you will be blessed by a nice variety of birds.

Offer the cheap stuff and grocery store blends and I will have your birds.

Well, it's time to fly for now.

Before I go, here is your positive thought for the week.

"Hope is the thing with feathers that perches in the soul -

and sings the tunes without the words -

and never stops at all".

Emily Dickinson

Feathers are important, andmentioned in the bible as well.

"He will cover you with his feathers, and under His wings you will find refuge;

His faithfulness will be your shield and rampart".

Psalm 91:4

"Treat the earth well:

It was not given to you by your parents,

It was loaned to you by your children.

We do not inherit the Earth from our

Ancestors, we borrow it from our Children."

Ancient Indian Proverb

Your friend indeed,

Ron Patterson

PS. If you enjoy these letters, please forward them to friends, family and co-workers.

Better yet, have them sign up so they can receive their own letters.

Gardening For Wildlife.

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