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Author Topic: Decorah North Eagles 2023  (Read 57602 times)

Ginger52

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Re: Decorah North Eagles 2023
« Reply #270 on: March 12, 2023, 02:51:11 PM »

Puff -- Amy discussed this in her March 1 blog post.  https://www.raptorresource.org/2023/03/01/march-1-2023-news-and-nestflix-from-decorah-and-decorah-north/

"Intruders continue to roil activity at the North nest. RRP master bander Dave Kester checked it out on February 27 and reported three adult eagles quite close to the north nest. As we suspected, DNF is spending most of her time guarding the nest and chasing the strangers away. Unfortunately, we’re getting a really excellent look at the ways in which eagle populations limit themselves, something we’ll be writing more about.

Why has DNF been spending so much time away from her eggs? Broodiness is caused by hormonal changes. After egg number one, testosterone and progesterone rapidly decrease while prolactin, a hormone that induces incubation and brood patch swelling, rapidly increases. The intruders might be boosting the production of hormones that prohibit or interfere with broodiness."

STLbf

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Re: Decorah North Eagles 2023
« Reply #271 on: March 12, 2023, 05:32:14 PM »

Great to have the explanation of DNF's un-egg-attentive behavior.  Yet, she is still nearby and comes to the nest even if it is only a safe place to stash food in her mind.  A second clutch is not impossible, but probably unlikely by now.

Late afternoon, MrN grabbed the  rabbit remains and flew them to the lower branches, where he quickly consumed them, then returned to his nest duties.

STLbf

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Re: Decorah North Eagles 2023
« Reply #272 on: March 13, 2023, 12:20:55 PM »

Morning at DNN.  MrN on duty as expected.  DNF came for a short visit about 10:30.  Great closeups, thanks to the cam ops.

STLbf

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Re: Decorah North Eagles 2023
« Reply #273 on: March 14, 2023, 04:16:19 PM »

Today so far, it's all MrN, and the egg.

STLbf

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Re: Decorah North Eagles 2023
« Reply #274 on: March 15, 2023, 05:26:06 PM »

DNF has been pheasant hunting!  About 8:00 this morning, she brought the carcass of a female Ring-necked pheasant to the nest. What a gift for MrN, who immediately flew away.  She left soon, MrN returned, and the carcass remained mostly undisturbed until after noon.  DNF came back, MrN left, and she moved the carcass to the edge, away from the egg, and defeathered some and ate a good meal. I'm speculating that letting the carcass sit for several hours loosens the feathers, making it easier to consume.  Does anybody know if this is true?

The head and neck had already been removed when DNF brought this bird.  Photos on AllAboutBirds.com confirm that it is a female.  This time of year is breeding season for pheasants, which are plentiful in this part of Iowa.  Eagles catch them every year that I've been watching.  My guess is that the pheasants are more interested in breeding than in watching for danger, so they are easy prey.  The adults are large, and MrN might have trouble hauling one up to the nest.

Pheasants are popular game birds in the midwest.  My father used to hunt them, and I have his recipe for delicious pheasant in wine sauce.  I don't hunt, but the recipe works with chicken.  Send me a PM if you would like the recipe.

STLbf

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Re: Decorah North Eagles 2023
« Reply #275 on: March 16, 2023, 12:02:45 PM »

MrN is doing his best to protect the egg from rain this morning.  Such a trooper!

STLbf

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Re: Decorah North Eagles 2023
« Reply #276 on: March 16, 2023, 02:34:06 PM »

Mid-afternoon, MrN flew off, DNF came in to pick at the remaining pheasant bones, cleaned herself up on the Ladder Branch, then flew off.

STLbf

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Re: Decorah North Eagles 2023
« Reply #277 on: March 17, 2023, 12:26:26 PM »

Couple of visitors around the nest area this morning, one red-tailed hawk in brushy trees and a female red-bellied woodpecker on a tree trunk.  See pics, and I might find exact locations later on the rewind.

MrN has been on and off the nest, and DNF paid a short visit.

STLbf

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Re: Decorah North Eagles 2023
« Reply #278 on: March 17, 2023, 04:55:14 PM »

What's going on with the Norths?  MrN left the nest about 1:00PM and DNF perched in the Love Tree about the same time.  There was another eagle with her, but I didn't see it arrive. It was a young sub-adult, see pics.  They seemed peaceful.  When the youngster moved too close, DNF wing-flapped and it flew away. 

Several minutes later, MrN flew in from the creek direction to land on the lower Love Branch, see pic, then flew back to the nest.  DNF stayed in the Love Tree for a while, did not see when she flew away.  From the nest, MrN did some challenge calling towards the creek.  Then things settled down again.

STLbf

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Re: Decorah North Eagles 2023
« Reply #279 on: March 17, 2023, 05:11:50 PM »

Backing up the rewind, I found when DNF and the young sub-adult arrived at the Love Tree.  Before 1:00, there were 3 eagles soaring around the area, see pic of 2 of them. DNF landed and was followed shortly by the sub-adult, see pic with colored circles.  It's probable that the third soaring eagle was MrN.

BrokenLug

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Re: Decorah North Eagles 2023
« Reply #280 on: March 17, 2023, 07:23:13 PM »

Well it's not sounding to good for the one egg laid here at the DNN so far this 2023 season:    :(
https://www.raptorresource.org/2023/03/16/nest-guarding-and-intraspecific-intrusions/

Mr. North sure was a dutiful Dad, kudos to him.  8) #1
DNF did what she is 'hardwired' by evolution to also do.  8) #2

Quote from: RRP
Had the intruders moved on quickly, been a less threatening combination of age and sex, or stayed away from the nest, things might have gone differently.
But we believe that her response to the constant presence of adult female intruders interfered with her ability to lay eggs and produce prolactin, aka the incubation hormone.
While Mr. North underwent incubation-related hormonal change, DNF guarded her nest, mate, and egg. Instead of producing prolactin, her body was producing hormones linked to aggression, territoriality, and stress.

Quote from: RRP
Will the egg hatch?
It will not.
When I first began researching this blog, I still had some hope. But Mr. North ceased incubation around 6:00 PM on March 16 and the egg is completely covered with snow.

Mr. North has cared for this egg through ice, snow, rain, and intrusions. We admire his dedication and skill and hope that he and DNF are able to reclutch this year.

My 2 cents.
This outcome is not necessarily a bad thing as it shows that there is a healthy thriving population of Adult BE's in this region.
It's a testament to the conservation efforts of RRP and many other groups for many years (including us) to restore Bald Eagle populations back to natural normal's and an overall healthy balance in a given geographical area.

Quote from: RRP
* Eagle populations boom until they hit stasis or carrying capacity.
* Contests for breeding space may act as a density-dependent regulator of population growth by increasing adult mortality, and       
  reduce reproductive rates by impairing breeding pairs’ ability to provide for or protect broods.

Us "armchair" BE camera viewers add to and help raise awareness. Just by our eyes being on the camera and our positive word of mouth we contribute to this conservation effort significantly as well.  8) #3

So kudos to you all for watching the cams as you are an important component of the recovery of the species too.   8) #4

We all want to see appropriate #'s of BE eggs laid at the correct time of year for the best possible fledge outcomes >
Then cute BE fuzzheads vying for icky vittles come Spring > but but Yet >

A robust healthy population of adult nesting BE's are the key to future eaglets roaming hereabouts and we have that here in NE IA.    :)
U. S. A.

STLbf

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Re: Decorah North Eagles 2023
« Reply #281 on: March 18, 2023, 05:14:47 PM »

Quick check on the North nest via rewind; looks about the same as most days recently.  MrN on duty more than not, DNF visiting the nest for a short time then leaving.  While she was on the nest, a squirrel was gnawing on the support boards for some of the equipment.

Cold and windy today.

STLbf

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Re: Decorah North Eagles 2023
« Reply #282 on: March 19, 2023, 01:50:47 PM »

It appears from the rewind that MrN spent the night on a Love Branch and came to the nest at daylight, where he was napping happily in the sunshine while a coyote hunted nearby.  The coyote got a small animal, maybe a vole, good action by the cam ops.   :P

MrN flew off about 9:15, and returned to the nest with prey, possibly rabbit.  An older sub-adult flew in with him and perched briefly on a lower branch.  MrN hollered and the sub-a flew away.  MrN took the prey off the nest to a perch on or near the ground.  Continued next screen . . .

« Last Edit: March 19, 2023, 01:53:29 PM by STLbf »

STLbf

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Re: Decorah North Eagles 2023
« Reply #283 on: March 19, 2023, 01:55:23 PM »


DNF flew in from the creek direction and called for food.  MrN brought a chunk of the prey, and DNF ate it.  She puttered at the nest, ignored the egg,  and perched on the Ladder branches for a while, then flew away.  MrN returned to the nest about 10:30 and has been there since.

STLbf

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Re: Decorah North Eagles 2023
« Reply #284 on: March 20, 2023, 11:41:45 AM »

First Day of Spring

Looks a lot like the last day of winter at the North nest, but spring sounds are all around with the grackles calling and displaying, same for RWBs.  Deer were grazing under the nest area just at daybreak.  MrN off the nest during the night again, but back on duty this morning.
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