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Author Topic: All About Nests  (Read 35494 times)

jfrancl

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Re: All About Nests
« Reply #15 on: November 01, 2013, 03:59:03 PM »

Bob, that's great.  I'd be interested hearing any data he may offer.  Hope you hear from him!

 And thank you for posing some very interesting and thought provoking questions!

Faith

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Re: All About Nests
« Reply #16 on: November 01, 2013, 07:23:55 PM »

Isn't learning great?  Information brings up questions, more research, more questions, and more research.  We can learn something every day and still not know it all!  I love this Forum board!!

Bob1603

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Re: All About Nests
« Reply #17 on: November 02, 2013, 12:53:22 PM »

Bob,  though I don't have data on recorded artificial BE nest construction and  usage success, I do have a link to an artificial nest construction and illustrations from the USDA Forest Service.

http://books.google.com/books?id=9IvjoVbe0R4C&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

As I stated earlier I sent an email to the author of the pamphlet mentioned in the above link - here is his response.

Bob,
Thanks for your interest in artificial bald eagle nests.  The tripod structure described in Research Note 383 was a unique structure built specifically for a nesting pair here in Arizona.  There's a follow up article published in the Journal of Raptor Research (1983; pdf attached) that describes the rather unusual use of this structure as the original lake bed flooded a couple years later.  Those flood waters eventually washed the structure away.  Since then we have much improved our approach to constructing artificial bald eagle nests.  See attached pdf for Research Note 535 (1995).  This latest article includes a summary table for AZ, CA, and WA artificial nests, but as far as I know there is no centralized tally of all the nests that have been built over the years around the country.  It is not an uncommon practice.  I have helped build or consulted on the construction of nests throughout much of the bald eagle's range.   Plus the US Fish & Wildlife Service in East Lansing, MI, has developed plans for a different style eagle nest with a platform constructed mostly out of 2x4 lumber attached to the new nest tree.  A number of those have been built in MI.   Successful use by eagles remains very much a 50:50 proposition, as they can build their own nests within a week or so if they want.  Using artificial nests like 'bird boxes' to encourage nesting is an even less likely endeavor.  The greatest success comes from the replacement of a fallen nest or nest tree.  I hope this information helps answer your questions.  Thanks again for your interest!
Teryl G. Grubb


Mr. Grubb states that "Successful use by eagles remains very much a 50:50 proposition."   That is a percentage that I feel is pretty darn good because any eagle in any nest is a success.  He also mentions two other publications and I will try and get links to those.

jfrancl

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Re: All About Nests
« Reply #18 on: November 02, 2013, 02:38:52 PM »

Bob, unfortunately the links aren't working for me.  Anyone else?  Is it possible to remove the "s" from https?  Not sure if that will help.

Bob1603

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Re: All About Nests
« Reply #19 on: November 03, 2013, 01:54:14 PM »

I have some problems posting access to the Grubb publications in the Forum.  1. The URLs I have for the publications simply will not open - even after removing the "s" from http.  2. The publications are too large to post here because there is a limit on what the Forum will allow - even when I tried to post them one at a time.  Emailing them directly to a Forum member works fine so please let me know in a private message if you would like me to send them to you.  Thank you.

Emyrauld

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Re: All About Nests
« Reply #20 on: November 04, 2013, 09:56:08 AM »

Here in central Alberta, winter is settling in and our eagles have headed south.  My question is this.
What impact does their absence from their breeding territory for the 5 months or so  have on the nature and quality of their nests, bonding, etc.?  Is it different than that of eagles that remain in their territory year round?
A sense of humor can help you overlook the unattractive, tolerate the unpleasant, cope with the unexpected and smile through the unbearable....Moshe Woldoks

jfrancl

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Re: All About Nests
« Reply #21 on: November 04, 2013, 11:32:23 AM »

Emyrauld, BEs have a very strong nest/nest site  fidelity.  So provided that there hasn't been a take over upon returning, they would just resume nesting and breeding activities.   

Emyrauld

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Re: All About Nests
« Reply #22 on: November 04, 2013, 01:04:55 PM »

jfrancl:  In watching eagles at Decorah et al, it would seem that a fair amount of time and effort goes into nestorations at this time of year.   If the eagles aren't around to do it, I just wondered how they compensate for the lost time, or if they simply miss out?  We are experiencing overnight lows of -10 C (14 F) so our rivers and lakes will be frozen over shortly.  I am pretty sure those that have not left already will be gone soon.  They return early to mid March and eggs are laid mid April, I am told.  That's a lot of nest reno time lost.  I am just curious.
A sense of humor can help you overlook the unattractive, tolerate the unpleasant, cope with the unexpected and smile through the unbearable....Moshe Woldoks

jfrancl

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Re: All About Nests
« Reply #23 on: November 04, 2013, 02:12:16 PM »

Emy, pretty cold there! Brrr

Right now our Es are in a phase insensitive to light, opposite of the photosensitivity period and hormones haven't spiked yet.   So the nestorations are minor now and will progress as time goes on.  They do bond during this period but wont go full force with nest restoring until mid/end of Dec or so.   And they can get nestorations done in a very short period of time if they had to. BEs can build a nest in 1-2 weeks if necessary so nestorations can be done quickly. 

Thanks for participating in this thread and your great comments!

jfrancl

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Re: All About Nests
« Reply #24 on: November 06, 2013, 12:38:28 PM »

Average spacing of active BE nests in SE Alaska is about 1 active nest for every mile of shoreline or coastline.   

In Florida nesting territories can range from .6 - 1.2 sq miles. Bald eagle nests are spaced apart to ensure sufficient food for nestlings and minimal disturbance from other eagles.

glogdog

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Re: All About Nests
« Reply #25 on: November 07, 2013, 04:47:12 AM »

In The Bald Eagle, Gerrard and Bortolotti, it states, "As a species, the Bald Eagle appears to be an adaptable bird, even nesting on a giant cactus in Baja, California, a bare rock in the middle of a Saskatchewan river rapids, and a hayloft of a barn on the Niagara River."  It further states that BE's are "highly selective as to where they place their nests".  They generally build in dominant trees: big red and white pines in Minnesota, pines and cypresses in Florida and Douglas-firs, Sitka spruces, and cottonwoods in Alaska.

The actual tree has distinct qualities. "The Bald Eagle prefers a more secure site in the crotch of a tree sheltered from the elements.  An eagle's nest tree is usually alive but often has a broken, deformed, or a dead top.  Nest trees, regardless of their species, are stout for their height and large crowns."  It also says they will have a spacious canopy which is advantageous for the adults during takeoffs and landings.  The large crown provides a secure site in which to build a large nest.

Hey Bob - this part is for YOU.  (Keep in mind this book is copyrighted in 1988).  "Only a few Bald Eagles have nested on man-made nest structures. Sergej Postupalsky has witnessed some nesting attempts on platforms in Michigan.  Eagles have accepted a large tripod erected by Teryl Grubb in Arizona to serve as a substitute for a nest that blew down.  Similarly, eagles have used makeshift wooden pallet platforms to replace fallen nests."  This is like the Sutton nest in Stillwater, OK.  Here's a pic.

The book does go on to say that it is common to find 2 or more nests within the territory of a single pair of eagles.  The last thing I want to add from the book interestingly is this statement: "Usually the active and alternate nests are within a few hundred yards of each other".  Sound familiar?  ;D           
« Last Edit: November 07, 2013, 04:56:57 AM by glogdog »
glogdog

jfrancl

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Re: All About Nests
« Reply #26 on: November 07, 2013, 05:07:27 AM »

glog there is a photo in RRP's blog of a mated BE pair that "own" 2 nests in one tree in MN

http://raptorresource.blogspot.com/search?q=alternate+nests
« Last Edit: November 07, 2013, 05:43:04 AM by jfrancl »

glogdog

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Re: All About Nests
« Reply #27 on: November 07, 2013, 08:47:38 AM »

That's right, jf.  Thanks for reminding us of that!  How interesting is that, huh?
glogdog

Bob1603

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Re: All About Nests
« Reply #28 on: November 07, 2013, 01:20:24 PM »

Bald eagles have to be among the most fascinating of creatures - multiple nests (some in the same tree), artificial nests, shared territories, - it goes on and on.  You just got to love 'em! 

jfrancl

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Re: All About Nests
« Reply #29 on: November 23, 2013, 04:23:53 PM »

In thinking about N2, I recall Mark Stalmaster's breakdown of BE nest sizes and shapes.  He states that BE nests can take on a cylinder shape, a bowl shape, a disk or an upsidedown cone shape. 

Cylindrical nests usually are constructed between 2  upright branches that are paralel to each other.  Bowl nests are "cradled" by supporting branchesas well as the tree trunk itself.  Disk shaped nests are placed close to the trunk and placed above several branches mainly in one of a variety of pinelike trees.  Conical nests develop where the configuration of the tree branches allow the nest to be smaller on the bottom and becomes larger as it reaches the top. 

Here are some photos of N2 in the making.

https://www.facebook.com/media/set/?set=a.452176618152296.89585.103786266324668&type=1
or
http://www.facebook.com/media/set/?set=a.452176618152296.89585.103786266324668&type=1