Skip to content
June 10, 2017 / mws

2017 Codorus State Park Bald Eagles – Youth to Fledge

This is the 2017 story of a pair of nesting eagles in Hanover, PA.

All images are courtesy of the PA Game Commission and it’s partners.

– From Week 3 to Fledge

For purposes of this blog, I am going to call the adult male eagle “Hershey” and the adult female eagle “Hanna” as has been done in prior blogs.  For the 2017 season, eaglet number 1 (called H4) was born March 20, 2017.  Eaglet number 2 (called H5) was born March 21, 2017.  The “H” designation is for Hanover and the numbers correspond to the hatched eaglets since the camera was installed.

At the beginning of week 3 the eaglets were moving towards independence.  Eaglets are curious about their surroundings and will explore the nest.  As the temperatures rise, they like to get closer to the edge and farther away from the warmth of the composted center of the nest. It is rare they  fall over the edge of the nest at this age. The two competing instincts – curiosity and fear keep them exploring but just inside the nest rails. 

beginning of week 3 and approaching the rails

When they are young most of their weight is in their lower body and they don’t have the muscle or strength to pull themselves to the top edge of the nest. When they are closer to fledging it can be more of a concern as they will be wingersizing, branching and hop/flying across the nest and may misjudge.

At the beginning of week four, the growth rate of H4 and H5 was phenomenal!  Both eaglets were eating larger chunks at mealtime. H4 still got fed first most of the time, but H5 was getting his share too. There was always an abundance of fish on the nest provided by Hershey and by now the eaglets no longer completely fit under Hanna.

A few eagle facts to note:

The eaglets beaks will gradually start turning yellow and by the time they reach maturity around 5 years old it will be as yellow as their parents.  At just over 3 weeks old, they are around 1 foot high & their feet & beaks are very nearly adult size. 

Eagles do not sweat, so they need to use other cooling methods such as perching in the shade, panting, and holding their wings away from their body.  So on the unusually  hot April days, there was much panting and H4 and H5 intently searched for shade.

This year there seemed to be more incidents of intruders around the nest.  One situation involved a close fly by of a hawk.  On April 11th there was an incident where both parents rapidly returned to the nest and vocalized loudly at an intruder.  It was suggested by commenters that it was another juvenile eagle.  At all times, Hershey and Hanna protected H4 and H5 with all their might.

At around 3 ½ to 4 weeks the eaglets are able to get around the nest by ‘walking’ on their tarsus or leg bone (above the ankle) – sometimes called ‘walking on their hocks’.

They have neither the muscle nor balance to walk on their feet at that time. When the eaglets are about 6 weeks old they should be able to stand up on their feet. This development indicates increased balance and muscle strength.

At around four weeks of age the eaglet’s wingspan is approximately 18-22”, the tail length about 2” and the weight is approximately 5 ½ -6 ½ lbs.

H4 and H5  are nearly full size and their feet have grow to nearly the size of a human hand.  At this age they are starting to pick at food and flap their wings to build muscle.

Their black pin feathers are beginning to come in on the wing edges and tail and the pin feathers are starting to poke through on their heads and back.  In about two weeks they will be covered in their black juvenile “flight”  feathers.  On hot days, the eaglets perform their “clown walk” to the rails and become more familiar with the world around them.

H4 and H5 started to pick up sticks and nesting material and do a lot of self-preening and scratching their itchy pin feathers.  They have ferocious appetites and gorge on fish and small mammals whenever Hanna or Hershey bring in the food.  After a meal, both eaglets show full crops and take an extended nap.

Birds in general have a high metabolic rate, which demands that they “process” their food as quickly as possible. They must get it into a form from which they can extract the energy they need, quickly and efficiently. Eagles have adaptations for doing this.

Part of their stomach has turned into a “gizzard”, in which food is ground down to a fine consistency for rapid digestion. In eagles, this is also the place where “pellets” are formed. These are masses of material from prey that cannot be digested, such as fur, feathers, and occasionally bone, that then travel backwards from the gizzard up to the mouth and are cast out the mouth.

During the fifth week, H4 and H5 are about 18” long from head to tail with a 30” wingspan, and weigh about 6 lbs. Their beaks and feet are almost full size. They are eating bigger bites and will start taking turns eating the fish tails and squirrel tails. As a result, viewers see more pellets being cast, usually in the morning.  The eaglets are becoming more active in the nest. It is as this point the H4 and H5 began to build wing muscles by flapping their wings (called wingersizing).

This is the time in the eaglets young life when H4 and H5 focused on the behavior of their parents.  Whenever Hanna and Hershey initiated a takeoff, landed on the nest, tore food or maintained the nest, H4 and H5 paid attention and started to copy their behavior. The eaglets continued to learn skills that they will need to survive in nature.

During weeks 6 and 7, the eaglets attained 90% of their total weight and height. Both H4 and H5 were showing dark dark juvenile contour feathers. The full-sized beaks remained black, but had the distinctive end curve. Peak energy demand occurs around 30 to 35 days of age. One of the most reliable outward signs that chicks have moved past the period of most rapid growth and peak energy demand is when they begin to appear mostly feathered.

Hanna and Hershey were visibly absent from the nest more often.  However, the Codorus Marina watchers reported that at least one parent would often be in a nearby sentinel tree.  H4 and H5 spent most of their time alone preening, playing with sticks and holding nest material and sticks in their talons.  They could  stand and walk, and balance on their feet, and displayed wing stretching and flapping.

Mantling over the fish

About mid-May H4 and H5 started to pick at the prey but in general they still needed help unzipping it. Their appetites were ravenous at this point and the eaglets started to snatch portions of an unzipped prey to self-feed. They also began to display the mantling behavior. A mantle is a defensive posture in which the eagles spread their wings out, tuck their tail down, and vocalize to warn others to stay away. Another instance of mantling occurred  with Hanna and Hershey mantling when there was an intruder in the area.

Around the end of May, the eaglets were very active in the nest and were fly/hopping and jumping while flapping their wings. The young eagles were rail-sitting and gazing out at their “world to be”.  At this point H4 and H5 were preparing to start branching.  Branching is the process by which the young birds hop out of the nest onto the limbs next to it. This is a small step towards eventual fledging. Branching allows the birds to begin to really stretch their wings, improving their coordination and balance while building the muscles they’ll need for flight.

Fledging is the process of leaving the nest, and moving to the stage at which the nest is no longer necessary for the birds to rest and be fed by their parents. Both branching and fledging are processes, not precise events.
H5 scanning the area

H5 scanning the area

On June 7, H4 was very active in the early morning. Just before 7AM, the young eagle lifted off the branch and fledged!  H5 looked amazed and branched as high as possible to look around for his sibling.  Only the very tip of H5’s tail feathers was visible on the camera. Over the next few days, H5 returned to the nest to eat and rest.  Hanna and Hershey continued to bring food to the nest for both young eagles.  Mantling was immediate when the food arrived and H4 and H5 became aggressive with protecting their meals.

View of H5 branching

H5 remained in the nest and exhibited a very healthy appetite!  Early each morning, H5 was intently aware of comings and goings and would branch and hop/fly around the nest always looking out to the surrounding area.  You could almost see him thinking about how to accomplish his first flight.  About 6:30AM on June 10th, H5 fledged.  Hershey had visited the nest just before the fledge and H5 hopped around the nest, branched and then performed an almost soundless takeoff.  It was a heartfelt moment to know that the 2017 Hanover nest was successful and the two eaglets had grown into independent and capable young eagles.

H4 and H5 June 2017

From the time they hatch until first flight  is approximately 10-13 weeks (80 days). The young eagles will remain in the area for another 1-2 months. They will practice their flying skills and return to the nest for food which the adults will continue to provide.

The PA Game Commission eagle webcam provided thousands of viewers with endless entertainment this season. Hanna and Hershey once again proved to be capable, protective and alert parents to H4 and H5. The Eagle webcam has been an excellent resource for nature lovers and a good teaching tool for educators.  Thanks to the PA Game Commission and it’s partners for allowing us to have this incredible viewing opportunity!!

***Eagle Facts provided through research and webcam viewing. Sources include Wikipedia, Southwest Florida Eagle Group, PA Game Commission, the Clinic for the Rehabilitation of Wildlife, the Center for Conservation Biology, the Cornell Lab of Ornithology, and the Teton Raptor Center.

top of page

I am the eagle, I live in high country
In rocky cathedrals that reach to the sky

And all of those who see me, all who believe in me
Share in the freedom I feel when I fly

-John Denver

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: