Eagle Molting Process [Even Eagles Have Awkward Phases]

eagle molting process

Have you ever looked at your closet and thought to yourself: “It’s time to freshen up my wardrobe.”

Maybe you’re about to go on a date and you realize that your lucky Hawaiian shirt that your wore on every date you ever went on in college because “the ladies can’t get enough of it,” fits you a bit tighter than it used to, and if you lift your hands above your shoulders it would give your date a little “sneak peek” of your midriff. That would hamper your ability to dance to YMCA, and you can’t have a successful date without showing off your limber dance moves.

We’ve all been there. And it turns out we are not alone, eagles also experience this.

The bird that is, not the band. Well actually probably also the band…they are getting up there in age now.

A​bout once a year, eagles go through a process of freshening up their wardrobe which is called “Molting.” By “wardrobe” I mean an eagle’s feathers, which they shed and replace every year in preparation for the mating season.

S​o you can add “refreshing wardrobes to enter back into the dating scene,” to the growing list of shocking similarities between eagles and human beings.

T​o track this molting process, we are going to break it down into the preparation phase, the awkward phase, and the finished product. Picture it like “Extreme Home Makeover,” but instead of the home of a young family that somehow has eleven home schooled children, the thing that is getting a makeover is a majestic eagle.

The Preparation Phase

Before an eagle can go through the yearly molting to prepare for mating season, it first has to reach maturity.

W​hen eagles first hatch, they are covered in fluffy white plumage that is called the “Natal down.” Though adorable, the natal down is not suited for flight and must be replaced.

T​he natal down is replaced by a grayish plumage known as “thermal down” in a process that begins a little over a week after hatching. These feathers are more complex than the natal down they replace, but they are still not suited for flight.

thermal down of eagle molting

Three to four weeks after hatching, the thermal down begins to be replaced by juvenile feathers that become the large healthy feathers that we associate with eagles.

T​he shift from natal to thermal downs, and then from thermal downs to juvenile feathers, are both molting processes where the eagle sheds old feathers and replaces them with new feathers. These molts are more rapid and condensed than the molts experienced by mature eagles.

T​his echoes our human experience. Many of us experience significant style changes from the time we start middle school to the time we leave high school, which is a rate of change that remains unmatched as we walk through the rest of our lives.

Once an eagle has juvenile feathers, its molting process then falls into the yearly cadence that is the norm for mature eagles. The molt is regulated by the eagles hormones.

The cue for molt initiation might not be what you would expect: day length. That’s right, when the days start to become longer, the hormones levels that initiate the molting process begin to rise, and eagles begin to shed their feathers.

And when their feathers begin to shed, they enter the next phase of the molting process.

T​he Awkward Phase

H​ave you ever gotten a haircut that looked bad at first, but eventually grew out to look quite nice? That is what happens to eagles during the awkward phase of the molting process, to the extreme.

T​he Awkward Phase of eagle molting

During the awkward phase of the molting process, eagles quickly lose their existing feathers to allow the new feathers to replace them. The problem is, the new feathers do not just miraculously appear, it takes time for them to grow.

T​he result is a period where the eagle looks ragged, unkempt, and patchy. This is a normal, but difficult season for eagles as their lack of feathers makes their lives generally more difficult.

S​o difficult in fact, that people have even used an eagle’s molting season as a metaphor for the spiritual experience of having a “dark night of the soul,” which, from a molting eagle’s perspective, would be quite rude…but I digress.

As the new feathers begin to grow, the eagle will spend more time preening and grooming itself. This is because the new feathers are covered in a waxy coating called “preen oil,” which the eagle needs to spread evenly over its feathers to keep them in good condition.

Molting can also affect an eagle’s ability to fly. As the old feathers fall out and new ones grow in their place, the bird’s wings may become uneven or unbalanced.

However, during the molt process, eagles can lose up to 40% of their mass, which helps offset the adverse effects their molting has on their ability to fly.

But just like every middle schooler, eventually eagles make it through the awkward phase of molting and are ready for mating season.

T​he Finished Product

Once an eagle completes the molting process they are filled with the confidence of a dad who just bought a new sports car…they’re ready for mating season.

the finished product of eagle molting

T​heir new and freshly preened plumage is smooth and stiff, which allows them to soar through the air without using much energy at all.

T​he appearance of a freshly molted eagle’s plumage varies greatly depending on the species of eagle. In fact, eagles have some of the most diverse plumages of any sub-species of bird.

O​n average, an adult eagle has around 7,000 feathers. These feathers are incredibly strong and light.

Altogether, these 7,000 mature feathers way around twenty ounces combined, which is about as heavy as a basketball. These strong, yet lightweight feathers allow eagles to fly at speeds of over 150 miles per hour…which is absurd.

Not only do freshly molted feathers help eagles fly at great speeds, or soar with little energy, they also prepare them for mating season. And who doesn’t love mating season?

Because, as it turns out, even eagles need a little confidence boost before they jump back into the dating game. And as a human, there is some comfort to be felt in knowing that.

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