Eagle Education and Information

[shuff1]

So, given Lucky Lady's suggestion and in respect of the original Sr Members I am starting this thread for people to share information on eagle habits, behaviors, research etc.

Thanks Lucky Lady for the great suggestion.

[kato9tales]

Okay, I will try here.  I was wondering if anyone knew what determines the number of eggs per season.  In the video I watched, the female produced only one egg.  The first year, this Decorah pair produced two, but since then has produced three per season.  Any ideas?  If I had time to Google, I probably would never have found this Forum.

[eaglewingvc]

not sure i understand  --  if there are questions that stem from behavior or research that are prompted by something related to the Decorah nest, where do we post?  both places?  since just about everyone here is interested in the Decorah eagles, why do we need to go to two places looking for information?  seems cumbersome but perhaps you can explain it to me.

not against this but just don't see how it makes the experience easier and more informative for everyone - confusing to me, but i am not too saavv!

[maewest1]

I can't figure out how to post.  I was on UStream all the time the eaglets were there and I miss the chat.  Can someone tell me how to post to this site?  Thanks!
Maewet1

[Pagent]

Okay, I will try here.  I was wondering if anyone knew what determines the number of eggs per season.  In the video I watched, the female produced only one egg.  The first year, this Decorah pair produced two, but since then has produced three per season.  Any ideas?  If I had time to Google, I probably would never have found this Forum.

The short answer is that the female determines the number of eggs.

Beyond that it is very technical in that the female can store the sperm and it can fertilize multiple eggs. 

[FinnBMD]

Fertility may have something to do with how the female fared through the winter months or it may be tied to the amount of food available when the female arrives at the nest territory;  it also could be the fact that some females are genetically predisposed to lay more eggs than others.

[Pagent]

Okay, I will try here.  I was wondering if anyone knew what determines the number of eggs per season.  In the video I watched, the female produced only one egg.  The first year, this Decorah pair produced two, but since then has produced three per season.  Any ideas?  If I had time to Google, I probably would never have found this Forum.

The short answer is that the female determines the number of eggs.

Beyond that it is very technical in that the female can store the sperm and it can fertilize multiple eggs. 

In the same breeding season, one mating can fertilize multiple eggs at multiple times. Females can store sperm in pockets off the infundibulum and this stored sperm can be used to fertilize future eggs. The mechanism of how the sperm is stored in a viable manner is not known. It is believed that the sperm might be “good” for several weeks but not likely until the next breeding season.
Dave McRuer, MSc, DVM, Dipl. ACVPM
Director of Veterinary Services
Wildlife Center of Virginia   
 

[shuff1]

ot sure i understand  --  if there are questions that stem from behavior or research that are prompted by something related to the Decorah nest, where do we post?  both places?  since just about everyone here is interested in the Decorah eagles, why do we need to go to two places looking for information?  seems cumbersome but perhaps you can explain it to me.

not against this but just don't see how it makes the experience easier and more informative for everyone - confusing to me, but i am not too saavv!

I think that we can continue discussion about the Decorah eagles here with the additions of other interesting informationi about eagles that we come across.  The original members (senior and hero members) felt that our conversations had become too diverse and had run afield of their original intention.  So I think that we (the newbies) can continue as we have been in this thread.  Hopefully many of the newbies will migrate to this thread and it will feel the same.

[Pagent]

i have deleted the two "technical" posts I made today on the Decorah Eagle thread that dealt with hearing and mating.  I have also reviewed all my post to be sure they are living room posts and not sports bar!!

[shuff1]

Ha, Pagent,

I was thinking about doing the same thing but I will need some time to do that since I was pretty chatty!

I think it would be great if people want to scoop up their 'non-living' room posts and carry them over here to the sports bar!  (or not)

[elfruler]

I do hope that these 2 threads don't end up dividing those interested in the Decorah eagles between Ustream chatters in one thread and long-time forum members in the other.  That was certainly not my intention.  Threads should be defined by topic, not by a particular group of people.

[shuff1]

Elf, I agree with your comment.  We don't want to divide people by groups only to segregate our conversations and topics.  Hopefully, this addition will encourage the more wide-ranging discussions and help to restore the original atmosphere of the Decorah eagles thread. 

I plan on visiting both threads and keeping my posts relevant and appropriate depending upon the thread.

As you are well aware the Ustream chatters (including myself) are more accustomed to a pretty wide variety of discussion.  Again, hopefully this will help to remind us of our focus depending upon which thread we are participating in.

[Faith]

Thank you, Shuff!  I'm going to try following both threads to see if one suits me better than the other.  I expect I will enjoy both! 

[elfruler]

Thanks, shuff, this forum actually is a perfect place to make the conversations that we all want to have easier to follow and to participate in.  I'm so glad you started this new thread, and pretty soon I'm sure it will sort itself out as the place for folks to have those detailed discussions of eagle biology, behavior, etc., that some find so fascinating.  And the Decorah Eagles thread will continue to be the place to revel in our beautiful family!

For those of you still a bit confused about how to navigate here, just think of the forum as chat, except with room dividers -- one conversation is going on here, another there.  Please feel free to migrate from room to room!  Won't it be a lot more fun to have good, satisfying conversations, than to try to shout to make oneself heard?  And get frustrated if no one answers?

[squeeaglee]

I hope this is the right place to post this:  The information following evolved from topics, questions, subjects from the other site, today but I think this is where I should post it.  Everything within can apply to any Eagle nest. 

Most imprinting is done in the first weeks. The term imprinting is used to describe ‘animal learning’ which occurs at a specific stage in the animal's life. Imprinting can take a variety of forms, but the more common type of imprinting is called filial imprinting.  This is what Finn described today:  11:27:42am Some studies show Eagles do recognize each other by feather, pattern and color, (any eagle, not individual) which it is believed is the reason sub-adults, or birds not ready to breed  are sometimes not attacked by other male eagles.  The change in color in an Eagles feather is said to be hormonal.

Other then Dr. Nielson’s excellent books, a couple of others on Raptors are:  The Birds of Prey - Scott Weidensaul;  Raptors of Eastern or Western North America -Brian K. Wheeler and for photographs,   A Photographic Guide to North American Raptors - Wheeler and Clark

Male or Female: It is my understanding that Bertolotti’s scientific measuring of the Hallux (the toe claw) and the depth of the beak  are considered highly reliable relative to gender.  Infact the blood test of Eagles that were later placed in wildlife centers for one reason or another, were gender checked, & on many occasions fully supported previously measured Eagles based on Bertolotti’s “theory” .  E2 is a female.   Generally female eagles are larger than male eagles in order to facilitate her need to cover as best she can, growing eaglets.  The male is considered the primary hunter during those times, and his smaller body allows the agility to fly between the trees, and catch numerous prey. 

As to vocalization, there are still so many unfinished on-going studies involving the Bald Eagle.  We do know that songbirds must learn to vocalize, however Eagles don’t really need to do that.  Eagles vocalize, and do “call” to each other, just not in a human sense; more of an “ok, I  recognize you” then a “Hi, how ya’ doing” .   They do have a distress call (scream) and will use that in attack!  It is generally agreed that when food is brought to the nest, everyone calls more out of  exuberation/excitement, just as today when the Juveniles see Mom or Dad approaching the nest.   There are those that claim they can tell a male Eagle call from a Female call based on pitch.  I’m not one of ‘em. ;-)  Interestingly I do know that most movies with Eagles use the call of a Red Tail Hawk.  That was pointed out to me when very young, and has “played” true throughout my life thus far.

Earlier I posted:  The nest belongs to the Male Eagle.  He built it to begin with to attract a mate.  IF a Male looses his mate, he will continue to maintain his nest, he will continue to protect his territory.  If a Female looses a mate , and she has eaglets or nestlings, within the nest, she will fiercely defend that nest.  IF there are no eggs or eaglets  and she doesn’t  pair with a new male that is approaching,  she will be asked to leave and she will.   

To add to that:
As some know another dominant male may attempt to take over a nest, at any time.  There have been documented cases where the father/nest owner has been driven out by a superior male with eggs being incubated.  The female will often accept him as her new mate, and he will take over hunting, fishing and raising another Dad’s eggs/eaglets, to include the mate.  If another male “wins” the nest and the female has no eggs, she will either decide to stay with the dominant male or fly away to one she likes.

And….did you know?  A young bird’s heart starts to beat around 72 hours after the start of incubation. At this time, the heart has only 2 chambers but will eventually divide into 4; two atria and two ventricles.