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Biological Sciences

College of Arts & Sciences

FAQ and Bald Eagle Information


What is fledging? Fledging is an event rather than an ongoing process. It is the time when birds make their first flight. In bald eagles this typically occurs around 12 weeks of age. 

What is branching? Branching is a developmental milestone when the chicks begin to venture out of the nest and into the surrounding limbs. It typically begins at about 9-10 weeks of development. 

When does an eagle's head and tail feathers turn white?  Eagles reach maturity by their 5th year.  From a young eaglet, each year they will gradualy change until completely white at age 5.  Sometimes they may have a little brown but not often.

Three Eggs For the first time since ETSU has been filming the Johnson City nest, Shima delivered a third egg on 2/7/2018. Bald Eagles primarily lay 1-2 eggs and it's rare for a third egg.  We are excited to share this nesting season with everyone.  3 eggs 2018

Egg Hatching, Shared by Michelle France from the Facebook ETSU Eagle Cams: This is an interesting article from Journey North, on what is going on inside the eggs before they hatch. Eagle eggs hatch one to several days apart depending on when they were laid. Eggs hatch consistently after 35 days of incubation. About 4 days before hatching the chick develops an egg tooth at the top of its bill. From inside the egg the chick pokes a hole in the membrane separating it from the air bubble at the top of the egg shell. Still inside the egg, the chick takes its first breath into the air bubble. and draws in its first breath. This bit of air will provide energy to scratch a hole through the egg shell to the outside. The hole poked through the membrane is called the internal pip. The hole pecked through the egg shell is called the external pip.After breaking the membrane with its egg tooth the chick can breathe the air that filters through the porous egg shell and vigorously starts the final process of hatching. The chicks hatch from the eggs without any help from the parents.The chick uses its egg tooth to scratch around the inside of the shell in a circular path. The scratches weaken the shell in a pattern all around the egg. This is called pipping, and it can take from one to two days. When pipping is completed the chick gives a few expansive bursts and the shell opens up During hatching, a chick must undergo several physiological adaptations. Before it hatches, a chick absorbs oxygen through the shell by way of the mat of membranes under the shell. During the hatching process, the chick must cut the blood supply to these membranes and trap the blood within its body. The chick must also absorb the yolk sack into its body and inflate its lungs for survival outside the egg.If eggs don’t hatch, adults will initially continue incubating, then start spending longer periods off the eggs and eventually give up.  Copyright 1997-2017 Journey North

12/20/2017 Buff City Nest Update by Kevin Brooks:  Raccoons disrupted the Bluff City nest.  It was too late by the time baffling was added to deter the racoons and the eagles moved to another tree.

1) We still have one active nest in Johnson City. Let's watch our Noshi and Shima, and have an amazing nesting season! We literally have all of our eggs in one basket this season, so let's show them some love.

2) Michelle France, our fantastically dedicated BC fans, and myself will continue to check on the currently abandoned nest through egg-laying season (mid February). It is possible we could have a Great Horned Owl or Red-tailed Hawk pair take over the nest as these species are known to readily take over abandoned eagle nests. Great Horned Owls should nest in January and Red-tailed Hawks will nest in March so hope is not yet lost. With some luck we may have to change our name to ETSU RaptorCams or something. There is even a small chance that Frances and Eugene will go back to the nest. Let's just stay optimistic for now.

3) If the current nest remains unused this season, I have already made contact with the landowner where the new nest is located. He is more than willing to allow us rights to put cameras on the new nest tree. It is too late in the season to move the cams this season, but it will be a relatively"easy" thing to set up for next season. That's great news!

Are there certain times of the day that one or the other parent are off the nest and flying, hunting, perching, in the area?  Both parents take turns on the nest incubating the eggs and very soon taking care of the eaglets. So when one is on the nest the other one is off flying, hunting, perching, etc. in the area.  Early in the morning right at daylight they have an exchange usually, after that you just never know during the day, also in the evening right before it gets dark you should be able to see a fly-in of ever who was out last. Right now there's just a lot of incubating, things will pick up once the eggs hatch.

Why does it look like there's a bright light on the nest at night even showing "shadows"  of branches, etc?  It looks bright but it is not and it does not disturb the birds. The thing is, infrared light is completely invisible to the naked eye. So it doesn’t look like a bright light is flooding the area from the outside, but it actually is—your eyes just can’t see it.   

Furthermore, night vision footage from cameras always looks black and white because human eyes can differentiate between black and white better than they can with other shades of colors, like red or blue. Because of that, most night vision cameras switch to a monochrome filter to make it easier for us to see the image.

Johnson City Nest:  Began in 2012, successfully fledged 9 chicks to date (2017)Bald Eagle FAQ and Info

Buff City Nest: Began in 2011, successfully fledged 11 chicks to date (2017)

*Both nests are located on private property, but Johnson City nest can be viewed from Winged-deer Park.*

How do you tell them apart? Shima, our Johnson City female has a deep notch in her white hood where it meets her chest. She is a darker bird than the male, Noshi, and she has black markings in her tail feathers.

Eugene (male) and Frances (female) in Bluff City are more difficult to tell apart. Frances is larger and darker than Eugene and also has a deep notch in her white hood where it meets the chest.

In general Bald Eagle females are larger and darker than males. A female’s halux (back talon) is around 2” long whereas a male’s is only 1.25”. A females bill will be larger and deeper than a male’s as well.  

Female eagles are up to a third bigger than males, so if you get them side by side it's easier.  

In general, Bald Eagle makes have brighter whites in the plumage and darker around the eyes.

What is the story behind naming the eagles?  There was a contest to name the eagles the first season. The Johnson city nest; Noshi and Shima comes from the Native American meaning Father and Mother.  The Bluff City pair is named in honor of the original land owners.

How big are the eagles? Bald Eagles are 28"-38" long from beak to tail with a wingspan of around 7'!

How big is the nest? The initial nest takes about 3 months to build and is around 4-5' wide and 2-4' deep. A pair of eagles will continually build on the same nest for years, so it becomes a massive structure!

When are eggs laid? Eggs are laid in early February and take an average of 35 days to hatch

How long until the chicks leave the nest? Bald Eagle chicks will fledge at around 10-12 weeks old.

Why are the eagles panting? Panting in birds show some level of discomfort. This could be anything from anxiety, nearby predators, or overheating. Here in East TN, we have highly variable temperatures.  Oftentimes they pant to cool down, similar to other animals.

The chicks are all alone! Have they been abandoned? No! The parent birds are always nearby keeping watch. The chicks require less and less incubation as their feathers grow.  Also, keep in mind that as the eaglets mature they don't need the parents except for fish or food. 

Where do the eaglets go once they are grown?  The fledglings from the first couple nesting cycles should be dispersed several miles away by now. The fledglings from recent years are likely somewhat close by trying to find territories of their own. They'll have run-ins with Noshi and Shima which will help push them further out to find hunting grounds of their own away from other adult Eagles. It's difficult to say without proper tags for our Eagles, but that's a likely scenario. 

I saw a bald eagle in Limestone, TN (or another local town):  Usually bald eagles stay close to their nest.  This could be one of the grown eaglets from one of the local nests or another bald eagle who is living near the waterways in the area.  We are not able to track our birds but appreciate knowing when others are around!

Don't forget, if the question you seek is not here you can always click on the Facebook link (Eagle home page) and post a question.


Bald Eagle Information
Haliaeetus leucocephalus

The Bald Eagle is the United States' national bird and is an easily recognizable species even to the casual observer. No other bird has a bright white head and tail with a massive yellow bill. Bald Eagles belong to the family Accipitridae, which also includes hawks, kites, harriers, and Old World vultures. The scientific name roughly translates to "White-headed Sea Eagle," which is appropriate because these birds are almost always nesting around water.

EagleAt the time the cameras were erected, Our Johnson City nest had been used for 3 years and our Bluff City nest had been used for 4 years, and you can see how enormous they already are! Eggs are hatched in about a month's time, and nestlings remain in the nest for 2-3 months. Young Bald Eagles appear all dark with their dark bill and a mottled mix of brown and white plumage. It typically requires 4-5 years before the young develop the characteristic yellow bill with white head and tail of an adult.

Nidification and the Young- Bald Eagles mate for life and show high fidelity to the same nest. They build truly impressive nests, where they can lay up to three dull-white eggs per breeding season. As part of their courtship ritual, mated pairs of Bald Eagles bring nesting material in the form of twigs and branches to the same nest year after year. An adult Bald Eagle can nest once a year for more than three decades, so the nests can potentially weigh well over a ton!

Diet- You can gain information about what a bird eats by examining its bill. Bald Eagles with their strongly hooked bill are chiefly piscivorous, fish eaters, but they will not pass up an easy meal. Bald Eagles can be seen eating carrion and the occasional small mammal or bird.

Size­- As in other birds of prey, Bald Eagle females are about a third larger than their male counterparts. A large female may have a wingspan of nearly 7 feet and weigh as much as 14 pounds! Males by comparison have a wingspan 5 ½ -6 feet and weigh 10-12 pounds. Bald Eagles from northern populations are larger than those from southern populations, an ecological principle known as Bergmann's Rule.

Habits- Courtship displays in Bald Eagles are fascinating. The pair will join talons at great heights and spiral downward, only separating at the last instant before inevitable impact. Northern populations of Bald Eagles tend to be migratory to escape harsh winters, whereas our East Tennessee Bald Eagles are permanent residents. These birds can be seen soaring on thermals, rising columns of warm air, in search of their favorite meal of fish.

Longevity- Bald Eagles in the wild typically live around 20 years, with the oldest one on record being 38 years old. Captive birds can live longer. One Bald Eagle in a zoo in West Stephentown, NY lived to be 48 years old! Many factors can affect wild Bald Eagles' lifespan, including: vehicle collisions, power line and fishing line entanglements, gunshot, famine, poisoning by ingesting lead shot, and disease.



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