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Author Topic: Bald Eagles Fact of the Day  (Read 18036 times)

tulsaducati

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Bald Eagles Fact of the Day
« on: April 10, 2020, 02:32:21 PM »

At one week of age, the hatchling becomes a nestling, and continues to grow extremely quickly. By the end of its first week, the nestling may weigh around 16 ounces. At around 9 to 11 days, the secondary down (or thermal down) begins to appear.  This down is much darker, thicker, and woolier than the natal down.
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eaglesrock29

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Re: Bald Eagles Fact of the Day
« Reply #1 on: April 10, 2020, 11:50:10 PM »

For April 11, 2020

Eaglets spend most of their first week of life gaining weight. The eaglets aren't able to thermoregulate* yet, so depending on the weather and temperature, they have spent a lot of time under Mom or DM2.  We've been observing them eating, sleeping, scuffling, and growing stronger each day as they interact with one another.  They will grow from about 3.2 ounces at hatch (about the weight of 18 nickels) to about one pound in their first week.  This is an increase of about 5 times their weight in just in seven days!  Who is counting out 18 nickels now to see how much they weighed at hatch?  :)

Today, D34 and D35 are six days old and D36 is three days old!

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*thermoregulate means regulating their own body temperatures.  That takes about 15 days.   
"When a storm is coming, all other birds seek shelter. The eagle alone avoids the storm by flying above it. So, in the storms of life may your heart be like an eagle's and soar above." - Anonymous

gardengirl

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Re: Bald Eagles Fact of the Day
« Reply #2 on: April 11, 2020, 10:58:38 AM »

Periods of Growth:


 eaglet: anytime from hatch to about 10 weeks from leaving the nest.

 hatchling: first week ,

 nestling: first week to fledge

, fledgling: while perfecting fledge,


 juvenile: when 1st set of feathering grows in and for the first year,

 Immature or subadult: after 1 year until adulthood.

 Some of these terms can overlap.
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pyrmum1

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Re: Bald Eagles Fact of the Day
« Reply #3 on: April 12, 2020, 08:25:38 AM »

Behaviors in raptors are: imprinted, innate (or instinctive), and learned.  A raptor's behavior comes from these 3 components and their interactions.  Imprinted behavior happens early in life and is basically unalterable, as is innate behavior.  Learned behavior can be modified during the life of the bird.
« Last Edit: May 18, 2020, 07:50:42 AM by pyrmum1 »

oregonian1944

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Re: Bald Eagles Fact of the Day
« Reply #4 on: April 12, 2020, 09:28:50 AM »

Bald eagles do not have vocal chords, so the sounds they make are done by passing air through the bones in their neck.  The sound comes from an area called the syrinx where the windpipe is separated going to the lungs. They have 3 main vocalizations: contact calls between mates, peal calls which are territorial calls and begging calls from the eaglets.

Bald eagle calls: http://www.allaboutbirds.org/guide/bald_eagle/sounds


pyrmum1

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Re: Bald Eagles Fact of the Day
« Reply #5 on: April 13, 2020, 08:31:13 AM »

Imprinting has five main parts to it: imprinting on parents, imprinting on siblings, development of fear response, imprinting on a future mate, & imprinting on the type of nest style, and habitat.
Imprinting occurs within the brain of the eaglet as it focuses on its food source (the parent eagle). The eaglet recognizes another of its species and learns to recognize itself as an eagle. 

pyrmum1

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Re: Bald Eagles Fact of the Day
« Reply #6 on: April 14, 2020, 11:06:48 AM »

Innate behavior is also called inherited behavior or instinct.  All raptors are genetically programed to react certain ways in particular circumstances in their life.  Interactions of various instincts (characteristic of the species), individual temperaments, & biological drives determine what reactions will be.  Each bird also has a different capacity for storing information in its memory. 

Examples of instinctive behavior (innate behavior) include, but not limited to: courtship behavior, copulation, nest building, incubation, and rearing of young.

pyrmum1

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Re: Bald Eagles Fact of the Day
« Reply #7 on: April 15, 2020, 08:01:33 AM »

LEARNING:  Involuntary learning leads to involuntary response or lack of response through the non-conscious part of the nervous system. This behavior is prompt, automatic, and unthinking.

Voluntary learning produces conscious voluntary responses.  They are not automatic and are not necessarily immediate. Once it is learned, it can't be unlearned.

A fairly higher level of learning is when a bird learns a behavior through watching & trying the behavior for itself. Learning enables them to adapt to a the ever changing environment by acquiring new behavior patterns.  Most behavior has both innate and learned components. 

jfrancl

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Re: Bald Eagles Fact of the Day
« Reply #8 on: April 15, 2020, 08:04:23 AM »

Bald eagle chicks are hatched with natal (or primary) down.  Down feathers typically lack a rachis and do not form a vane.  At about 10 days of age the secondary (or thermal) down will begin to emerge.  The natal down will eventually be pushed out by contour feathers.   
Please join us in our campaign to GET THE LEAD OUT. Together we can make the world a safer place for Bald Eagles and all wild life. We need you, THEY need you!
http://raptorresource.org/forum/index.php/topic,765.0.html

Pansie

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Re: Bald Eagles Fact of the Day
« Reply #9 on: April 15, 2020, 10:57:51 AM »

Nestlings @ 2 weeks
From 9-twelve days old, the nestling's cere (the fleshy covering at the base of the upper mandible) is a pale olive color. The legs are a pale yellow color with areas still a pink-yellow color. Within certain boundaries, the nestling can thermoregulat by 15 days, having thermal down to keep them warmer.  The parent Eagles can be absent from the nest at a slightly longer periods of time. They are close by at all times, protecting their young.  The nestlings also have unique calls that prompt adults to bring them food.

gardengirl

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Re: Bald Eagles Fact of the Day
« Reply #10 on: April 16, 2020, 07:10:28 AM »

On average nestlings gain about a pound every 5 days. The male eaglet gains approximately 3.5 oz a day while the female gains about 4.6 oz a day.
The largest relative weight gains are early in the nestling time frame. Between the ages of 18 and 24 days the eaglets gain more rapidly than at any other stage of development. Bartolotti found sexual size dimorphism (females being larger) begins  to appear in some variables at about 20 days of age.
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glogdog

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Re: Bald Eagles Fact of the Day
« Reply #11 on: April 17, 2020, 06:19:53 AM »

Dr Bryan Watts from the Center for Conservation Biology says there are 3 stages of development in a young eagle's life: Structural growth, Feather growth, and Neurological development.  Structural growth appears early in their development and includes primary tissue growth of the skeletal and muscular systems.  An example of this is the "clown" feet.  The second stage is feather growth: natal down, thermal down, juvenile feathers, and flight feathers which continue to grow throughout the developmental period.  Then the final stage, the neurological one, includes walking, feeding, and flying which occurs in the final month as they acquire the coordination necessary for movement and flight.   
glogdog

Iriscats

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Re: Bald Eagles Fact of the Day
« Reply #12 on: April 17, 2020, 07:46:12 PM »

It's hard to see the the remiges(  flight feathers of the wings) and retrices (flight feather of the tail) emerging at 20-25 days, followed by the countour feathers at about 27days because of the thick layers of the thermal down

jfrancl

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Re: Bald Eagles Fact of the Day
« Reply #13 on: April 18, 2020, 07:22:38 AM »

At 13 days old and 10 days old, we can still see those little ear holes on D's 34, 35 and 36.  They are located below and to the right of the eyes. Eagles and other birds do not have the external "pinnae" or ear lobes that we have. Specialized auricular feathers that protect the ears while in flight will grow, and will allow sound to funnel directly to the ear.

https://www.youtube.com/watch?v=s1rACzeWQcs
Please join us in our campaign to GET THE LEAD OUT. Together we can make the world a safer place for Bald Eagles and all wild life. We need you, THEY need you!
http://raptorresource.org/forum/index.php/topic,765.0.html

TX_Ninja

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Re: Bald Eagles Fact of the Day, April 19
« Reply #14 on: April 19, 2020, 12:14:08 AM »

Iriscats's post about wing and tail feathers reminded me of this video of a golden eagle.

Golden Eagle in slow motion Earth Unplugged https://www.youtube.com/watch?v=aM0JMoGABgk

retrices = director/helmsman = tail feathers;    remiges = oarsman = wing flight feathers
I like the video. The Latin definitions of the feathers make sense

I was the geek that took Latin in high school, so I like the Latin explanations for the different feathers. Kind of a cool feather and flight demonstration and explanation.

Not long and the eaglets at Decorah will begin to sprout their "real" feathers.