Message From The Director

Although Bob Anderson is gone, the Raptor Resource Project is committed to continuing his work. We are dedicated to preserving and strengthening raptor populations, expanding participation in raptor conservation, fostering the next generation of preservationists, and educating people around the world about raptors and their habitats.

Our board met on Saturday, August 1st, to choose a new director and add additional board members. Bob wanted John Howe to succeed him as director.  John and Bob worked together on several projects, including the falcon cam installation and HD upgrades at Great Spirit Bluff, the Decorah cams, our bald eagle cam project with the Seneca Nation of Indians, and preparation for the Philippine Eagle jungle camera.  Bob was impressed by John's leadership and technical skills, his passion for using media to fascinate and motivate people, and his dedication to our mission. John will be a wonderful addition to the Raptor Resource Project and we welcome him as our new director. He will move Bob's legacy forward.

From left to right: David Lynch, John Dingley, Dave Kester, Laura Johnson, Neil Rettig, Brett Mandernack, Director John Howe. Not pictured: Board Chair Randy Christman, board members Jim Robison and Ken Mueller.

The Raptor Resource Project also added four new board members to the original five picked by Bob. Veterinarian Laura Johnson and film-maker Neil Rettig are our leads for carrying the Philippine Eagle Project forward, Dave Kester is deeply involved in our peregrine falcon banding and monitoring program, and David Lynch has been involved in a wide variety of projects, including eagle tracking, the kestrel nest box program, and social media. All nine of our board members were friends of Bob and are deeply committed to our mission. They will continue Bob's work, assuring that his vision guides us.

Message from the Director

John Howe

With the passing of Bob Anderson, renowned raptor expert and advocate, Raptor Resource Project friends and fans around the world are experiencing a profound loss. I want to thank all that shared their sentiments by cards or postings, or who traveled to Decorah to celebrate the life of a truly amazing man!  Bob was a visionary man, a humble man, and most of all a man with purpose.  He was an intelligent scientist, an expert raptor researcher, and breeder determined to help save the Peregrine falcon after decades of DDT use brought the species to the brink of extinction. Bob spent much of his life savings on Peregrine recovery efforts.  He challenged conventional ideas and developed an innovative program to release Peregrine falcons from the river bluffs where he found success in drawing the falcons back to their original nesting habitat.  He pioneered and perfected bird cams through his work with Excel Energy and RRP.  Bob also opened an educational window of awareness into the intimate daily lives of raptors for anyone to see, making it possible by partnering with an innovative company called Ustream.  His collaborative work with cinematographer Neil Rettig led to the installation of cameras in the famous cottonwood at the fish hatchery and the world famous Decorah Eagles!

What an incredible legacy Bob Anderson leaves behind, a legacy I am honored to have been chosen to move forward.  Allow me to introduce myself.  My name is John Howe; some of you may know me as GSBDweller.  I grew up in the scenic bluffs of the Mississippi River north of La Crescent, MN along Apple Blossom Scenic Drive.  Ironically, I never saw Peregrine falcons in the area growing up.  In 2004, Bob approached my father about installing a nest box on our family property.  He drew my father in to participate in his goal of returning falcons to this cliff that they inhabited decades ago.  The nest box has attracted falcons back each year since and our family, friends, and falcon enthusiasts band the young each spring.  I can’t tell you how rewarding it has been to work with Bob over the past five years.  It all started with a discussion at a banding event in 2011.  I commented to Bob “You have a wonderful bald eagle camera broadcasting to Ustream, but your life passion has been falcons. How would you like a falcon cam out on the bluffs of the mighty Mississippi?” Bob jumped at the chance to help my son Jonathon design and complete his Eagle Scout project.  It consisted of laying 1,000 feet of conduit and cables though the woods and he and Amy Ries did the hard part of hanging across the cliff and mounting the camera and cables to the nest box.  At the time, I thought - what kind of crazy people dare do this kind of work?  Now, after their expert training, I have been hanging around with them!

Bob was clear about his plans for the future.  We are committed to bringing those plans to reality while coming to a better understanding about the unpredictability of Nature.  We did not expect to lose the current Decorah cams to lightning and we sure had no idea that a storm would topple the current bald eagle nest (N2).  It is interesting that Bob understood that unpredictability and we were already preparing for a backup Decorah cam location before that unfortunate event.

We have an aggressive and exciting agenda being put into motion and the expertise of our long time and newly appointed board members will be harnessed.  Here are the first four items of Bob’s “Top 10” project list that we are moving forward with:

1. Restoring the Decorah Eagle nest. Bob was very excited by Neil Rettig's suggestion to build a starter nest near the ruins of N2 to see if the eagles adopt it as their own. Neil will be leading this effort and it is truly a remarkable idea. Will they come if we build it? The question has implications for wildlife management far beyond the Decorah eagles.
2. Establishing a new bald eagle nest cam in Decorah.  We anticipate a September installation of cameras in a beautiful oak tree in the vicinity of one of Iowa’s treasured trout streams.  There are challenges in getting this nest instrumented and “on-air”, but everything is falling into place for an new pair of eagles to introduce.
3. Partnering with the Seneca Nation of Indians to establish a bald eagle cam at one of their active nest sites. This is a wonderful opportunity for the Seneca Nation to continue its heritage of educational outreach.  This eagle cam will be hosted on RRP’s Ustream site.
4. Establishing a live Philippine Eagle Cam at a wild nest. Bob’s initial RRP work with the Philippine Eagle foundation and Neil Rettig led to the installation and broadcasting of a captive eaglet produced as part of the PEF breeding program.  That video footage is still posted on the RRP Ustream page. RRP is collaborating with Cornell Lab of Ornithology to install nest cams in the dwindling forest habitat of the Philippine Eagle.  We are very excited about the impact this project will have in educating the Philippine people and the world about an amazing creature that is facing an uncertain future.  Just like Bob’s falcon work, this project could be the catalyst for the next great conservation success!

Wild Philippine Eagle. Photo by Neil Rettig

Thanks to all of you for your past and present support as we start on a very exciting year of raptor research, education, and monitoring!  We will keep you posted on our progress.

John Howe

What Bob Anderson Meant to Me - Mainecoonlady

A post from a follower that I wanted to share...

It was 2009 when my Mom was diagnosed with Alzheimer's. Over the next year at home, she became increasingly worse with the onset of Dementia as well.  This drew on my ability to work, and I lost my job (career really) as well.  Soon Mom entered the hospital with pneumonia and was released to a rehab facility.  So my days were filled with constant battle with the repulsive care of my Mom in really bad health facility conditions.  In 2011, I found the Decorah Eagle Nest Cam.  I was enchanted.  I read and learned all I could about the work done by the Raptor Resource Project, Bob Anderson and our Eagles.  While not much into the science of things, I was just so amazed at their beauty, grace and freedom.  Freedom.  That word has become very important to me.

I watch the camera, and observed the chat.  2011 was an amazing time.  It was new and exciting.  So my days were filled with the horror of watching my Mom slowly slip away, and fighting literally for her care and health when so many wanted to give up on her and settle for substandard care.  It was very exhausting and demanding.  I was alone.  I was scared.  I was heartbroken. So each day, after tucking Mom safely in her bed, I drove home, ate some awful fast food and sat down to watch the nest.  Not chatting back then, but watching and listening.  Escape?  I watched these magnificent creatures build up the nest, mate, produce beautiful eggs that hatched into these precious little white fluffy bobbleheads.  To this day their sweetness brings tears every year.  I watched them eat, sleep and grow.  I waited breathlessly for the wingersizing, worried in the snow and the rain (yeah.. I know NWZ! But ya worry), I watch branching and the Y activities.  Then the most amazing thing happened.  FLIGHT!  I watched one by one as those little babes took off.  It was exhilarating. Freedom, in my world was unattainable both for my Mom and me.  But when they took off for the first time I felt their freedom deep inside that touched my soul.

I watched, I listened, and learned all I could.  I was living in hell by day and freedom and wonderment each night.  I read articles, watched videos, watched all I could on Facebook and on RRP website.  Then there was that first transmitter.  Our Diva D1 was now on her way and we took that journey with her.  ESCAPE!  I found escape in her freedom.  I could not escape from the agony of the daylight but I lived for those nights with the eagles.

When the CAM was down for the season repairs, I kept up with the day to day through Facebook, RRP and even tried the Forum. In October 2011, Mom lost her battle and now I was left alone for real.  Camera was down for the season, and Mom was gone.  I had taken a useless part time job that at least allowed me to keep going.  I moved in with my sister and rented out my house, since nothing was selling.  It was a rough couple of months and a lonely winter.  I had lost everything I treasured.

Then there was activity in the nest.  Our parents we preparing.  So busy, so intricate in the design. Finally the camera was back and the life cycle had begun again.  D12, that regal elegant eaglet; D13, the steady faithful sidekick and D14, the most amazing little creature I have ever seen.  I learned a new phenomenon.  Our eaglets have individual distinct personalities.  D14 will forever be etched in my heart with his loving style, silly antics, camera technician abilities, and that sweet little white speck above the eye.  The original CAM HAM.  In 2011, I learned about eagles, in 2012 I fell in love with them.

Then the heartbreak. There was Bob.  It was at this point I learned that he was not just a scientist, he was a fan.  That big burly down to business man, loved them too.  I was intrigued. He was so business-like about the goals that needed to be reality for all the raptors.  He was the most compassionate man, the most informative leader, he understood that he brought a beautiful treasure to us and with this, he felt this enormous sense of responsibility to the raptors and to us.  He would post a message that was factual and scientific, informative and hopeful in the face of tragedy.  But under it all, was a great man with a huge heart.  He made a family with this nest, not only with Mom, Dad and their offspring, but with us. Over the years, I joined chat, participated with questions and information.  I am proud to say that I am part of that chatter family now.  FRIENDS.  Bob opened a world of beauty to us and gave us each other, he gave us friendship.

My life in these past four years is very different.  I finally have a great job, not like I had but a good solid job where I feel my talents can contribute.  Being out of work does crazy things to your self-esteem.  Then I bought a small townhouse, and recently sold the other house, finally.  I followed the amazing yet tragic 2012, the unknown 2013 with N2, the horrendous 2014 season, and this year's 2015 stellar year for our eagles.  And through it all was Bob, like a rock, like the leader of the pack. He worked behind the scenes taking care of our eagles, falcon, turkey vultures and so many more.

Bob? I know you are listening now.  Do you know what your work meant to our eagles?  Do you know what your life meant to all of us?  You gave me peace in turmoil, you gave me fun in the face of despair, you made me care about something besides the darkness in my life, you educated me about something I didn't even know I cared about, you got me excited about wildlife, you made me spread the word and get my friends to check out this amazing new camera event!!!  YOU Bob!  Now multiply that by the millions around the world who love this as much as I do.

I can't express my gratitude for all you have given.  I know your work will continue but you will be missed.  You will be remembered as a hero, to our raptors and to me.  You saved them and you saved me, in more ways than you can imagine.  I will remember your smile, your tender voice, your caring drive to care for our raptors and bring us a joyous event, console us through the tragedies and give us hope for the future.

Thank you, Bob Anderson.  Those words just don't seem like enough.  You will be missed.  Hug our babes for us, D12, D14, D18 and D19.  You are our eagle angel now!   You are B1, the one and only!

Mainecoonlady

Falcon Effigies of the Upper Mississippi River

This article was first published in the Newsletter of the Iowa Archeological Society
Spring 2015, Issue 232, volume 65 No. 1.

When we began our efforts to return the peregrine falcon to the bluffs of the Mississippi River in 1998, we collaborated with Effigy Mounds National Monument in Harper's Ferry, Iowa. Effigy Mounds National Monument runs along the west bank of the Mississippi river. It preserves prominent bluffs, unfragmented forests, and over 200 prehistoric mounds constructed by groups of indigenous people more than one thousand years ago.  The mounds usually take one of three different shapes:

• Conical mounds that are round and dome shaped
• Linear mounds that are long and tubular
• Effigy mounds that are shaped like birds, bears, panthers, snakes and other animals  

I became very interested in the mounds while we were hacking young falcons from Hanging Rock, located at the north end of the Monument.  I learned of stunning aerial images of effigy mounds outlined in white lime and photographed from small planes.  We owe these images to the late Dr. Clark Mallam, a professor of anthropology at Luther College in Decorah, Iowa from 1940 to 1986.
Dr. Mallam believed that the effigy mounds were works of art. He conscripted his students to haul hundreds of 50-pound bags of Luther College football field lime out to the bluffs to outline the monuments, while he photographed their work from using small airplanes.  Altogether, Dr. Mallam recorded 220 mounds on film. I still run into students who smile while recalling the monumental effort it took tote the lime out to the bluff top mounds and photograph the mounds.

When I first viewed Dr. Mallam's aerial images, I was immediately struck by the shape of the bird mounds, which greatly resemble the silhouette of a peregrine falcon.  The similarity inspired me to research mound builder culture. Over the past decade, I have found a great deal of evidence to prove that the bird mounds are in fact falcon effigies. The mounds resemble falcons, the mound builders venerated falcons, and the mounds are often located near historic falcon eyries.

Figure 1: Two falcon effigies

This aerial image of two falcons is located on private property adjacent to an historic falcon eyrie near Lansing, Iowa.  The falcon on the right has a wingspan of 227 feet and the falcon on the left has a wingspan of 141 feet.  These two falcon effigies are the largest bird effigies remaining in the State of Iowa.  Their long wings and general body plan resemble falcons more than eagles, hawks, or generic passerine birds.  LIDAR, or Light Detection and Ranging, shows the resemblance even more clearly.  LIDAR is an optical remote sensing technology that can measure the distance to properties of ground targets by illuminating the target with laser light and analyzing the backscattered light. The spectrum it uses penetrates foliage and provides high-resolution ground surface imaging.

The LIDAR image below was taken of a Wisconsin bluff top along the Mississippi river. It shows drainage, watershed topography, and a detailed image of a falcon effigy, which has a wingspan of 271 feet. If you look closely, you will see the falcon's head is directed left. Visitors to the mound report that it appears to have a curved beak.

Figure 2: LIDAR image of a falcon effigy

A professor at Luther College in Decorah, Iowa, told me soil analysis revealed that some of the material used to make these massive earthen effigies was mud gathered from the river bottom.  I was completely shocked since sometimes we have to haul ropes and gear from the bottom of the bluff tops to band falcons, a lung and leg-busting effort even with modern backpacks and hiking gear. I can't imagine the amount of work it would have taken to haul thousands of pounds of mud up to the bluff tops, which tower 400 feet over the river in some places.  Surely, the effigy builders would not have bothered unless the project was grandly important to them.

Figure 3: More effigies of four bears, two falcons and one linear mound.  Each of the bear effigies are approximately 85 feet long.

Several decades ago, I was standing below a large cliff near Lansing, Iowa.   An elderly gentleman approached me and asked what I was looking at. I told him about our falcon reintroduction work and expressed the hope we might someday have falcons back at their historic cliff nest sites.  He enthusiastically responded, "You mean duck hawks!" and went on to tell me that duck hawks were his entertainment before radio and television.  Fifteen years after we began our cliff-directed releases, I now understand what he meant.  When I carry out my spring cliff surveys, I look for peregrines hammering bald eagles, the occasional golden eagle, red-tailed hawks, red-shouldered hawks, and (to a lesser extent) turkey vultures as they make their way up the Mississippi river flyway.  This territorial behavior by the falcons is nothing like crows mobbing an owl or black birds mobbing a hawk. The defending falcons put on an amazing, acrobatic show: diving, chasing, and loudly vocally protesting as they drive away or outright kill birds many times their size.  This impressive sight must have inspired the mound builders to build falcon mounds and adopt the falcon as a model for warriors who achieved leadership through daring feats in war and hunting.

Growing up in Minnesota, I was accustomed to seeing Indian mounds.  Minnesota at one time had over 11,000 known mounds.    Most were conical mounds varying 25 to 40’ in diameter and three to eight feet high.  However, one mound in northern Minnesota measures 100 by 140 feet and is 25 feet high. The mound is composed of 5,000 tons of earth and thought to contain the remains of thousands of individuals.  Most mounds served as burial sites, although some of the effigy mounds appear to have been purely ceremonial in nature.

The remaining falcon effigies along the Mississippi river are commonly found near historic falcon eyries. Sadly, far too many mounds have been destroyed.  In 1892, Theodore Lewis surveyed the Harpers Ferry, Iowa “Great Group” of mounds.  He identified approximately 900 mounds, of which 274 were effigy mounds.  By 1973, less than a dozen badly disturbed conical mounds remained.  This hallowed ground had been plowed under or dug up, and the graves robbed of their bones, implements, and ceremonial artifacts. The largest mound group ever recorded in North America was all but gone.

I first began looking for falcons on these cliffs thirty years ago, in 1983. I longed to see them back where they truly belonged, as mound builders and earlier generations had. Thirteen years later, I was tired of waiting. I moved to northeast Iowa, built a rock-lined eyrie with the help of several friends, and raised falcons for release. Not everyone approved of the project. The peregrine falcon was still endangered and our proposed cliff releases attracted a great deal of controversy, especially since earlier release attempts had failed. However, I believed that it could be done. We persevered and, despite influential opposition, received the backing of the Iowa DNR and Effigy Mounds National Monument. We hacked falcons in 1998 and 1999 from Hanging Rock at Effigy Mounds, an arduous process that required a 100-mile round trip and a three-mile mosquito-infested hike along a muddy, narrow trail every day, for over 40 days each season.

In 2000, the first falcon returned to the cliffs of the Mississippi river at Queen's Bluff, a large cliff located south of Winona, Minnesota. The unnamed female was a cliff hack from Effigy Mounds in 1998. Our project had worked! The move, the fighting, the planning, the building, releasing, driving, and hiking - all of it had paid off, and falcons were back! The long wait was finally over and we had accomplished our goal.

The falcons return from their winter haunts toward the end of February. As soon as they take up residence on the bluffs, every migrating bird of prey on the Mississippi flyway has to run the gauntlet of the territorial falcons. Sometimes when I am down below a river cliff, I see a migrating eagle or hawk making its way towards a cliff with falcons. I wonder: will this bird catch the wrath of the territorial falcons? Just as it nears the cliff, it loops out over the river, bypassing the cliff face entirely. It always brings a smile to my face. That bird has been educated.  But don't take my word for it... visit the Upper Mississippi River cliffs and come see it yourself!  On the river's east bank, the majority of the cliffs can be found from Diamond Bluff, WI south through Prairie Du Chien, WI. On the west side, the cliffs run south from Red Wing, MN to Waukon Junction, IA. It is a spectacular setting for a spectacular bird of prey, and an ongoing show.

We owe a special debt of gratitude to the many falconers who supported our work, along with the Iowa DNR and Effigy Mounds National Monument. Thank you for your support.

Our Brother Bob Anderson

Our brother Bob was number seven from a family of eleven brothers and sisters. We grew up in a small rambler in a new housing development in White Bear Lake with wide open fields across the street. It was common at that time for kids to leave home at the crack of dawn and not return until dinner time and Bob would take off on foot or on his bike every morning to explore the world. He was a regular boy, catching animals and bringing them home to observe – or in the case of snakes, bringing them home to tease us.

Our father started his own company and we moved to Rapid City South Dakota for a few years – keeping our home in WBL too. Bob was about thirteen at this time and I believe his love of birds started from exploring the Black Hills Mountain Range. I know that he also carried a small shotgun too because one time he returned home and told me he was attacked on a cliff by a large bird and he had to shoot to scare it – creating a hole in his gun case. He said he came real close to falling that day but of course that didn’t stop his love of exploring -he was back out there the very next day.

We returned back to WBL and Bob started a friendship with Bob Duerr – who was with Como Zoo. Injured animals soon found their way to our small rambler with the big fenced yard and one that I remember was an eagle, maybe a Golden Eagle with a broken wing. That eagle could outrun a rabbit and it was hard for us young kids to watch the kill but Bob said everyone needs to eat. We called that eagle Tom Dooley – after the Kingston Trio song Tom Dooley because even with a broken wing he was capable of hopping up on the fence, and would put its head on your shoulder. Bob Duerr also got Bob starring roles on the Lunch with Casey kid’s show which was very cool!

It was also at this time that Bob started bringing home the birds. We had a small room in our home, a kind of scary room we called the “back room”. This is where we stored our coats and boots and things and this is also the room Bob took over for his birds. So, you can only imagine how super scary it was to open that door to get a coat, not only knowing what would come flying out at you, but also wondering just how much bird poop it would contain!

He moved onto to Hawks and I remember several Red-Tails and also a beautiful Goshawk that he let me hold one day and it got lose. We chased that bird down for hours and finally got it back. Bob got a Volkswagen van and from then on was known as the Bird Man as he always had a bird in the back. One place he lived in was with another animal lover so there were snakes and spiders in cases everywhere and an alligator greeted you from the tub!

Bob loved flying his birds and learned everything he could about Birds of Prey – especially the Peregrine Falcon. His farm house in Hugo was always filled with fellow falconers sharing their love of birds. He worked for the Science Museum of Minnesota for a while and it was about this time that he married and they had a son Jeremy. To support his family – he tried to put his love of birds on hold and took a job with 3M but his passion was too big to control.

Around this time falcons were starting to die off and it was discovered that the pesticide DDT was to blame. DDT usage was poisoning the adult birds and causing the eggs to have very thin shells. The Peregrines were becoming extinct. So in the 1970’s DDT was banned and Bob and friends like Mark Bolton started attempting to artificial inseminate the birds. Bob would stay up many nights for months manually turning the eggs – replicating what nature would normally do. The process was successful and the first babies that were born were really something to celebrate! I do admit that I loved the look on our family’s faces when they first saw these newly hatched baby birds– not the prettiest for sure! The release birds found their way onto tall buildings and structures and luckily there was no fear of heights with Bob as he scaled buildings and cliffs to provide nest boxes and ban them for tracking purposes.

Our brother received so many National Awards but he always downplayed the recognition. Our eldest sister Pat tried to start a scrapbook and very quickly ran out of pages – Bob was everywhere. Bob was a humble man – and always quick to point out that his success were not his own. It was the contributions from so many others that made the projects successful – including the Eagle Cam. We, Bob’s family, are very happy that we were able to share our brother that we loved so much with all of you.

JoAnn Anderson
Pat
Ronnie
Dick
Judy
Caryl
Ken
Bob
Sue
Joyce
JoAnn
Greg

Bob Anderson

I am deeply sorry to confirm that Bob Anderson passed away this morning. Out of respect for Bob and his family, we are asking that everyone respect their privacy. Official announcements will be made here and on Ustream in the days to come. Our deepest condolences to Bob's family.

Although Bob was very proud of his work with the Decorah Eagles, his heart was truly in his peregrine falcon recovery work. This video tells the story of his cliff work and was a special favorite: https://youtu.be/USQs4Bwxa18

The photo shows him on Great Spirit Bluff. It was one of his very favorites - he loved to be on rope - and is how many of us will remember him. Fly on, friend and mentor. We will never forget you.

Decorah: the eagles, N2, and our plans

Camera and N2

As you might know, wind took down N2 in Decorah very early on Saturday, July 18. The limb that held the nest tree was sheared completely off, several trees in the immediate area were toppled, and a few rows of corn in the field near the nest were flattened. The eaglets and mom were quickly accounted for. Dad kept us wondering until Sunday morning, when he was spotted at a favorite perching place on top of the bluff near the hatchery. As sad as the loss of N2 is, it could have been so much worse. There was no loss of eagle or human life, the family wasn't using the nest, and Mom and Dad are in a period of latency. Once again, a traumatic event for us is simply a part of life for them.

So what's going to happen next? At this point, we are waiting to see what the eagles do. We expect that Mom and Dad will start building a new nest in the fall, most likely in October. We don't believe they will abandon their territory, although we don't know exactly where they will rebuild or whether they will go back to N1. We will be watching closely to see what happens. Will the question of alternate nests finally be answered, at least in this case? Will the eagles rebuild in the woods next to trout creek or choose another spot? When exactly will they start and what will it look like? Thanks to Jim Womeldorf's work in 2013, we have a great basis for comparison!

N2 from the back, splintered limb

Having said that, we can't guarantee a live stream from this location in 2016. Installing and cabling a camera is a huge project, especially if directional boring needs to be done. Once the eagles start working on a nest, we don't want to risk shifting them again. If we can find another solution - a ground cam, for example - we will, but it is hard to plan when we don't know what Mom and Dad will do.

Bob has been thinking about another Decorah eagle cam for quite some time. Eagles can nest anywhere, but a camera needs electricity and internet access - two things that are in short supply at many locations! Fortunately, he identified another possible location just this spring. We will be placing cameras there this fall while we wait to see what Mom and Dad do. If we can't put a camera in N3 this year, we will do it next year. If it is possible to put N3 online via a ground cam, as Jim Womeldorf did in 2013, we will. And if neither of the first two options are possible, we will continue to observe and report on Mom and Dad old-school style. 

A lot of people are asking how Mom, Dad, and the eaglets weathered the storm so successfully. Eagles and many other birds sense changes in barometric pressure hours in advance of incoming weather. While they can't forecast long-term changes in weather (a rough winter, for example), they do sense and respond to relatively immediate weather conditions. The eagle family and other area birds probably sensed the incoming storm and hunkered down in a safe, relatively sheltered area to ride it out. They have long talons with excellent gripping strength (400psi per talon!), and can change their aerodynamic characteristics by changing their shape. So the next time you know rough weather is in the forecast, watch the birds (and bees) and see how they react! 

A few links on the subject: 

• Birds predict weather change and adjust behaviour by reading barometric pressure
  http://phys.org/news/2013-11-birds-weather-adjust-behaviour-barometric.html
• Can animals predict the weather?
  http://science.howstuffworks.com/nature/climate-weather/storms/animals-predict-weather2.htm
• Natural barometer in birds evolved from ancient fish sense organ: http://www.cam.ac.uk/research/news/natural-barometer-in-birds-evolved-from-ancient-fish-sense-organ

Damaged corn

After The Fledge Weekend!

The eagles have fledged, but we haven't stopped having fun! Come to our After The Fledge party in Decorah, Iowa, from July 16 through July 19. Thanks to apex sponsor Ustream and the Decorah Chamber of Commerce for their support!

To register for the weekend, go here: https://goo.gl/MSmQ3T
For our forum thread on the event, go here: http://goo.gl/pUH3I1

Information

Thursday, July 16: Meet and greet at the opera house in Decorah's Hotel Winneshiek (map: https://goo.gl/SfJaFf).

• 5pm to 8pm: Enjoy drinks and snacks while you meet moderators and other eagle lovers. We'll have some souvenirs for sale and fun surprises for everyone!

Friday, July 17: Kayaking, scavenger hunt, and volunteering with the Humane Society!

• Kayaking, 1:00-3:30pm. Scott Iverson has planned a wonderful kayaking trip on the Upper Iowa in the Bluffton area about 15 miles north of Decorah. The scenery is spectacular and the paddling is great! For more information, follow this link.
• 1-4pm: Volunteer at the Humane Society of Northeast Iowa. Details TBA.
• Scavenger hunt, all day: The Decorah Chamber of Commerce has sponsored a scavenger hunt through downtown Decorah. Explore the area while racking up badges and competing for prizes! 

Saturday, July 18: Biking, talks, scavenger hunt, and dinner

• Biking, 9:00am. Hit Decorah's lovely paved bicycle trail with Jim Womeldorf and several Ustream chat mods. We begin meeting at 9:00 and hope to leave at 10am. See you on the trail! 
• Talks, 2PM: Valders Hall, Luther College. Printable map: http://www.luther.edu/campus/assets/campus_map_8.20.10.pdf.
  Google map: https://goo.gl/LKHavm
  Bob Anderson will introduce talks by Neil and Laura Rettig (Philippine Eagles) and Brett Mandernack (Bald Eagle tracking in the midwest). Neil and Laura will also bring their harpy eagle Cal. 
• Dinner, 5:30pm. Hatchery. We are serving delicious Iowa pork, chicken, and corn. Don't eat meat? We also have a wonderful vegetarian option! 
• Scavenger hunt, all day: The Decorah Chamber of Commerce has sponsored a scavenger hunt through downtown Decorah. Explore the area while racking up badges and competing for prizes! 

Sunday, July 19: Volunteer at the Humane Society of Northeast Iowa

• 10am - 1pm, details TBA. 

Friday - Sunday

• Tours of the fish hatchery (bring quarters to feed the fish!)
• 6am'ish: Coffee and pastry at the hatchery

We hope to see you there! 

Can Bald Eagles Get Avian Influenza?

Can bald eagles get avian influenza? That question is increasingly being asked of us at Ustream and on Facebook. The short answer: We don't know. But let's take a quick look at the landscape so far.

What is avian influenza?
To quote the USDA: "Worldwide, there are many strains of avian influenza (AI) virus that can cause varying degrees of clinical illness in birds. AI viruses can infect chickens, turkeys, pheasants, quail, ducks, geese and guinea fowl, as well as a wide variety of other birds. Migratory waterfowl have proved to be a natural reservoir for the less infectious strains of the disease.

AI viruses can be classified as highly pathogenic (HPAI) or low pathogenic (LPAI) strains based on the severity of the illness they cause. HPAI is an extremely infectious and fatal form of the disease that, once established, can spread rapidly from flock to flock."

There are at least two different HPAI strains circulating right now: EA/AM-H5N2 and EA-H5N8. The USDA tells us that: "The H5N8 virus originated in Asia and spread rapidly along wild bird migratory pathways during 2014, including the Pacific flyway.  In the Pacific flyway, the H5N8 virus has mixed with North American avian influenza viruses, creating new mixed-origin viruses.  This is not unexpected.  These mixed-origin viruses contain the Asian-origin H5 part of the virus, which is highly pathogenic to poultry.  The N parts of these viruses came from North American low pathogenic avian influenza viruses." The same thing appears to have happened in the Mississippi flyway with H5N2. It is generally believed that waterfowl migrating north carried the virus into Minnesota, although it isn't known how it spread to confined poultry. They most likely contracted the virus while wintering in areas shared with infected Pacific flyway birds.

At present, the USDA reports that:

• 114 avian flu detections have been reported.
• 21,644,473 animals have been affected. The vast majority have been on commercial poultry farms that raise chickens, turkeys, mixed poultry, and pheasants.
• The first detection was reported on 12/19/14 and the last detection was reported on 05/01/15.

While most of the detections have been reported in commercial poultry, wild birds can contract H5N2 as well. The vast majority of cases have been reported in waterfowl, including wigeon, canada geese, mallard ducks, wood ducks, northern shovelers, and teal. Unfortunately H5N2 has also been reported in birds of prey, including:

• Coopers hawks
• Red-tailed hawks
• Gyrfalcons

H5N8 has been reported in:

• Peregrine falcons
• A bald eagle
• A great horned owl
• Gyrfalcons

On April 30th, Minnesota Public Radio reported that a Cooper's hawk in Yellow Medicine County was the first Minnesota wild bird to test positive for the avian influenza virus H5N2. However, a positive test from a dead raptor only means the bird was exposed to the virus, not that the virus killed it or that the bird spread the virus to other birds. In this case, it was killed when it flew into a window and the virus was found after the carcass was sent to The National Veterinary Service Laboratory in Ames, Iowa.

So what can we make of all this? Based on what we know now, the eagles in Decorah and Fort St. Vrain don't appear especially likely to succumb to H5N2 avian influenza.

• While H5N2 can be spread through consuming infected prey, it has tended to spread in domestic animals after direct contact with fecal droppings or respiratory secretions of infected birds. This is less likely to happen in a highly dispersed bird like the bald eagle. The virus has only been reported in one bald eagle and a small handful of wild raptors.
• No large die-offs of raptors have been reported in Minnesota, Iowa, or Wisconsin. All three states are conducting surveillance programs to identify to what extent the virus is present in wild birds.  
• While waterfowl can carry the virus, it seems to primarily affect domestic large-scale operations. Backyard flocks of chickens have not been infected to nearly the same degree. The USDA has identified just 12 cases in backyard flocks, including five in Washington in January and February, plus others in Idaho, Kansas, Minnesota, Montana, Oregon and Wisconsin. Wild and backyard birds could have been exposed over time to low pathogenic versions of bird flu and developed stronger immunity as a result.

It is believed the virus will die as temperatures warm up and ultraviolet light increases.  In the meantime, I suggest the following links for more information, including influenza updates: 

• USDA tracking site. Lists all verified cases and is updated every Friday afternoon.
• Wild bird findings. Lists all verified cases and appears to be updated every Friday afternoon.
• Biosecurity for birds. Suggestions to keep your birds safe.

How are states responding?

• In Minnesota: http://www.dnr.state.mn.us/avianinfluenza/index.html. This is a great site that (among other things) provides information about how to report a dead turkey or raptor.
• In Iowa: http://www.iowadnr.gov/Education/IowasWildlife/AvianInfluenza.aspx
• In Wisconsin: http://dnr.wi.gov/topic/wildlifehabitat/birddiseases.html. Also includes reporting information.

News Articles

• MN DNR: Hawk from Yellow Medicine County tests positive for HPAI virus. http://news.dnr.state.mn.us/2015/04/30/hawk-from-yellow-medicine-county-tests-positive-for-hpai-virus/
• WQUAD8:  Bird flu moves south and east in Iowa. http://wqad.com/2015/05/04/bird-flu-moves-south-and-east-in-iowa/
• The Colorado Springs Gazette: Bird flu virus raises questions scientists working to answer
  http://gazette.com/bird-flu-virus-raises-questions-scientists-working-to-answer/article/feed/229462

Did you know?

In Minnesota, the DNR is working to identify the virus in wild birds. The agency is collecting waterfowl fecal samples throughout Minnesota; asking turkey hunters from Kandiyohi, Pope, Meeker, Swift and Stearns counties to submit their harvested wild turkeys for testing; and collecting dead birds of various species reported by the public. 

The DNR has collected 29 dead birds of varying species; nine have tested negative for the virus and 20 results are pending. Test results also are pending on the 37 samples from hunter-harvested wild turkeys. The agency has collected 2,749 waterfowl fecal samples – nearing its goal of 3,000 – and more than 2,200 have tested negative; results for the rest are pending. The waterfowl fecal sampling effort is designed to determine with 95 percent confidence whether the virus is present on the landscape in at least one percent of the waterfowl population. They really want to know if you find a dead turkey or raptor. Go to http://www.dnr.state.mn.us/avianinfluenza/index.html for more information.

The Raptor Resource Project has offered to collect samples while banding this year. I'm guessing the answer will hinge on whether or not we start seeing problems in the wild population. We will keep you informed if anything happens.

Red-tailed hawk growth and development in the nest

Eaglets aren't the only thing growing right now! The two eyas red-tailed hawks at Eaglecrest are morphing into adults right before our eyes. Like bald eagles, different parts of their bodies grow at different times and different rates, reflecting developmental priorities and impacting behavior. How will hawks EC2 and EC3 (also known as Speckle and Snickers on the Eaglecrest Wildlife facebook page) grow?

• 0-7 days: the culmen achieves maximum growth. Red-tailed hawks hatch with a culmen (the dorsal ridge of the upper mandible) that is about 30% of the maximum size it is likely to achieve in the nest. During a red-tailed hawk's first week of life, its already large culmen nearly doubles in length, going from an average of 6.9 mm in length to an average of 12.3 mm in length. Since the consumption of food is the root of all else besides, the hawk's food-consuming apparatus is given developmental priority. While the culmen continues to grow after week one, its rate of growth slows dramatically, becoming almost flat by week five. Bald eagles follow a similar pattern, although they have almost twice the growing time in the nest that red-tailed hawks do and their developmental milestones reflect that.  
• 7-14 days: third toe and tarsus achieve maximum growth. Eating has priority, but movement isn't too far behind. A young hawk needs to move to build muscle and feed once it is past the point where Mom and Dad simply stuff food into its waiting mouth. In the second week of life, a red-tailed hawk's third toe and tarsus are given developmental priority. The third toe is the real stand out here, nearly doubling in length from 16.9 to 27.9 millimeters. With longer toes and thicker, longer tarsi, the hawks are better able to sit up, move around the nest on their feet and knees, and interact with one another. We see a similar pattern with bald eagles, who reach asymptotic mid-toe and tarsus size about half-way through their nestling period - 40 days, in their case. 
• 14 to 21 days: body weight achieves maximum growth. With food intake well in hand, young hawks gain weight rapidly. While they've been growing all along, weight gain is the biggest actor in week three. The young hawks spend a great deal of time eating and sleeping as their weight increases. 
• 21 to 24 days: weight gains decline, independence increases. During the fourth week, weight gain declines, the nestling hawks begin feeding independently, and feather growth takes over. The hawks have the strength and physical structures they need to stand upright on their feet, manipulate food, and feed on their own. At about day 24, the length of primary seven overtakes weight as the best indicator of age.  At this point, fledge is just two or three weeks away. 
• 24 to 35 days: Feathers take front and center. As fledge comes closer, developmental energy is channeled into growing feathers. The primaries enter their maximum growth phase during weeks four and five, the two weeks prior to fledging. The young hawks will also be growing sub-adult feathers elsewhere, including their backs, their tails (which won't become red until molt two, in their second year of life), and their chests. 
• 36 to 44 days: Time to fly! Feather growth will slow, but the growth of flight-related muscles is happening in leaps and bounds. Wingercizing will take front and center stage as they young hawks practice for the big event by flapping, wing-hopping, hovering, and eventually taking flight! 

Both red-tailed hawks and bald eagles allocate developmental energy into producing weight and structure first (day 0 to day 24), and feathers second (day 24 onward). While feathers often seem light and simple, these two distinct periods of growth point to the incredible amount of energy needed to produce a proper 'coat' of feathers. Enjoy the hawks now, since they will be leaving the nest soon. It takes just 44-46 days to grow a red-tailed hawk from hatchling to fledgling! 

Watch live: www.ustream.tv/eaglecresthawks

Resources

• Analysis of growth of the red-tailed hawk. The Ohio Journal of Science. v83, n1 (March, 1983), 13-19. http://goo.gl/32lXK6
• Physical Development of Nestling Bald Eagles with Emphasis on the Timing of Growth Events
  The Wilson Bulletin, Vol. 96, No. 4 (Dec., 1984), pp. 524-54.
  https://www.usask.ca/biology/bortolotti/pubs/wb96-4-524-542.pdf

Did you know?

Red-tailed hawks are excellent falconry birds. While their are many excellent falconry organizations, I'm most familiar with NAFA. Interested in falconry? Follow this link: http://n-a-f-a.com/

A Four Recap

Earlier this week, a follower asked us for a recap of eagle Four’s life. Four was one of three eaglets that hatched in 2014. While early life in the nest was fairly ordinary, gnats and record-breaking rain interfered with fledging. For the first time that we know of, only one of the 2014 Decorah alumni successfully transitioned to life in the wild. One of Four’s siblings was injured and went to SOAR, where he  remains. The other sibling died of electrocution from a high voltage transmission line not far from the hatchery.

Four’s transition from fledge to flight was a bumpy one. During her first month on the wing, Bob rescued her from a location at the side of a highway, a fence, some deep woods, and a corn field. She roosted on the ground, traveled only short distances, and remained in the vicinity of the nest longer than any other eaglet we are aware of. We were starting to ask ourselves if Four would ever go when, on October 19, she abruptly left. Between June 22, 2014 and March 1, 2015, we received 302 valid fixes on Four. She traveled a total of 686 miles, averaging 2.2 miles a day. She achieved her furthest distance from home on January 8, 2015, when she was tracked 159 miles south of her natal nest. Her longest contiguous flight took place on December 1st, when she traveled 34.8 miles between the Maquoketa River and a roost near Lake McBride. She was electrocuted on March 2nd, roughly 130 miles south of N2.

After Four was electrocuted, we documented her death and reported it to the US Fish and Wildlife Service. We also contacted Alliant Power with photos of the pole under which Bob found her. When we were told it was up to code, Bob decided to get a second opinion. Contact number two told us that several things needed to be fixed to make the pole safe for birds. We passed the information back to Alliant Energy and decided to survey the area for more eagles. Two Ustream mods volunteered to conduct the survey for us. They didn’t find any eagles, but they did learn about another electrocution. They provided photos of that pole and several others. Alliant stated that they would fix the fatal poles and others like them. Thank you very much to IzzySam and Faith for taking this on for us.

We plan to take a trip back into the area where Four died to see whether Alliant fixed the poles as promised. The code we used to follow the travels of our eagles will be repurposed to map electrocutions and identify problem spots. While not every pole can be immediately protected, we can make dangerous poles a priority. Four touched a lot of hearts during her brief life. It is our hope that her death will bring about a safer environment for eagles and other birds.

Four's data is retained here: www.raptorresource.org/maps/latest.php.

What can you do?

• Find out whether your utility has an avian protection plan. If they don't, they should consider adopting one. An APP helps keep animals, equipment, and people safe. http://www.aplic.org/APPs.php
• Report electrocuted birds and other animals to your power company. Electrocutions are deadly to animals, harmful to equipment, and potentially dangerous to human beings. 
• Report collisions to your power company. While our eagles have been electrocuted perching on poles, collisions are also deadly. Swan diverters and other deterrents can be installed.
• If you are a member of an electric cooperative, make your concerns known to the board. I know of at least one electric cooperative in the process of retrofitting all their poles are safe. Electrocutions destroy equipment, require unscheduled repair time, and are expensive. 

Egg Colors and Shapes

The Chicago Peregrine Program inspired me to write a quick blog on the colors and shapes of eggs. Bald eagles have white eggs, peregrine falcons have eggs that range from light cream through brick red, and red-tailed hawks have pale eggs that are lightly splotched with brown. How and why do the birds we watch lay differently-colored eggs?

In general, female birds inherit egg colors and patterns from their female parents, who are ZW heterogametes. Egg-shell is made primarily of calcium carbonate, a white material, so the default color of all eggs could be considered white. As an egg moves down a female bird's oviduct, it squeezes or presses against glands that produce colored pigments from the breakdown of hemoglobin. Some colors (blues and greens) are applied very early on in the shell forming process, while others (brown) are applied quite late. Color may be applied relatively evenly or in drips and drabs depending on the bird and the speed of the egg through the female's oviduct. If the egg is stationary or moving very slowly, it may be solid, blotched, or spotted. If it is in motion, it will be streaked.

Coloring eggs carries a metabolic cost, so why aren't all bird eggs white? It's believed that birds with white or nearly white eggs have nesting strategies that hide their eggs from predators without the use of color. They might nest in cavities like barn owls, cover their eggs in vegetation like geese, or begin incubation immediately, like bald eagles. Since the eggs aren't visible to predators, camouflage colors and/or cryptic markings don't provide a survival advantage. Birds that lay colored eggs tend to nest in places or ways that are more visible to predators. Peregrine falcons, for example, don't usually begin full incubation until after their third egg is laid. The red color and light speckling helps conceal peregrine eggs when Mom and Dad aren't sitting on them and could make the eggs harder for nest invaders like raccoon to find. Ten or 20 seconds might buy enough time for enraged parents to drive nest intruders away.

So why do red-tailed hawks lay lightly speckled eggs while eagles lay white, highly visible eggs? Both birds begin full incubation right away and nest in fairly similar ways. We don't know for sure, although eagles in general are highly visible (giant nests, flashy black and white colors, six-foot wing spans) while hawks tend to be more concerned with concealment. The differences in egg-coloration might reflect some aspect of their lives we don't understand, but either way, egg-coloration is driven by survival. Hawks must need to conceal their eggs where eagles do not.

Predators aren't the only problem birds face. Some birds commonly dump or lay eggs in the nests of other birds. Splotched, spotted, or streaked eggs may help individual birds recognize their own particular markings and reject eggs that don’t match. So why don't Canada geese, which egg-dump, lay patterned or marked eggs? In this case, I suspect that non-parental eggs don't impact the survivability of parental eggs very much. Canada geese are precoccial, so young require less parental investment once the eggs hatch. Canada geese also time hatching quite tightly, so an egg dumped at the wrong time won't survive.

How about egg shape? Peregrine falcons, Bald eagles, and Red-tailed hawks lay differently colored eggs, but the eggs of all three species are elliptical or oval in shape. We used to think that egg shape was influenced by clutch size and the need to stack eggs, calcium availability, and/or 'the roll factor' - ie, heavily tapered eggs roll in a tight circle instead of rolling off ledges. But in 2017, Professor Mary Caswell Stoddard and her team found that the shape of an egg correlates with the hand wing index, a measure of the shape of the wing.  Faster, frequent flyers have longer, narrower, pointier wings, which translates into a high HWI. Birds that are weaker and less frequent fliers have shorter, broader, more rounded wings, which translates into a low HWI.

So why would flying ability influence egg shape? The maximum size or width of a stretched oviduct is constrained by a bird's body size. Faster, frequent flyers have reduced body sizes and abdominal cavities relative to weaker, less frequent fliers. Their muscular, streamlined body plans and narrower oviducts can't accommodate large, round eggs, but their eggs still have to carry enough nutrients to support embryonic development. These birds maximize egg volume by forming elliptical (oval) or asymmetrical (one round, blunt end and one narrow, pointier end) eggs that can pass through their narrow oviducts while still carrying the nutrients their embryos need to develop and grow.

So how do they do it? While I tend to think of eggs as being shaped by their stiff outer shells, an egg's inner membrane determines its shape. Birds that form elliptical or asymmetrical eggs lay down a membrane that is thicker on the big end and thinner on the pointy end. As an egg moves through a bird's oviduct prior to eggshell development, the thinner end is squeezed and elongated to produce an asymmetrical egg.

In general, egg color and shape is influenced by survival. Female birds that produce more young will out-compete female birds that don't. Egg-color and shape may be influenced by overall health (healthier birds tend to lay more vibrant eggs), metabolic cost, the need to hide from predators, the need to identify one's own eggs, and the shape imposed on an egg by the parent bird's body plan. In all cases, our parents have demonstrated egg-ceptional egg-care! We look forward to eggs soon!

Things that helped me learn and write about this topic:

• The Chicago Peregrine Program.
• Book: Oology and Ralph's Talking Eggs. I strongly suggest this book for the bird lover in your life. It is a beautiful book and a wonderful read. 
• A Moment of Science by Indiana Public Media.
• Avian Egg Shape: Form, Function, and evolution: http://science.sciencemag.org/content/356/6344/1249
• Science Mag: http://vis.sciencemag.org/eggs/
• Grrrl Scientist: https://www.forbes.com/sites/grrlscientist/2017/06/26/pointy-wings-pointy-eggs-birds-flight-abilities-influence-egg-shapes/#2ab494392caf

For more on birds of prey and body plan, read this blog: https://raptorresource.blogspot.com/2017/03/falcon-and-bald-eagle-body-plans.html

Decorah Eaglet Four Electrocuted

We are sorry to announce that Four, the single remaining bird from the 2014 Decorah alumni to remain in the wild, was electrocuted on Tuesday, March 2nd. This is the fourth eaglet from Decorah that we know of to die from electrocution. Bob and a good friend picked her carcass up on Thursday and Bob and Brett examined her on Saturday and verified the cause of death.

Bob found her lying underneath a utility pole. He took photographs and sent them to a consultant, who told us the pole was unsafe and made suggestions to improve the safety of this pole and other poles in the area. We brought them forward to Alliant Energy/Interstate Power and Light and are waiting for a response from them.

Why do the eaglets keep perching on power poles? Bob theorizes there is a behavior difference between urban and rural eagles. Rural eagles are programmed to perch in trees because that is what they have available. But urban eagles, including our beloved Decorah family, are exposed to power poles and other man-made structures from the beginning. There are vast amounts of power poles serving our needs.  With eagles beginning to nest in close proximity to man - something new for both species - he believes electrocution will be an increasing concern for urban-fledged eagles and utility companies.

What can you do?

• Find out whether your utility has an avian protection plan. If they don't, they should consider adopting one. An APP helps keep animals, equipment, and people safe. http://www.aplic.org/APPs.php
• Report electrocuted birds and other animals to your power company. Electrocutions are deadly to animals, harmful to equipment, and potentially dangerous to human beings. 
• Report collisions to your power company. While our eagles have been electrocuted perching on poles, collisions are also deadly. Swan diverters and other deterrents can be installed.
• If you are a member of an electric cooperative, make your concerns known to the board. I know of at least one electric cooperative in the process of retrofitting all their poles are safe. Electrocutions destroy equipment, require unscheduled repair time, and are expensive. 

We will continue our work with the electric distribution industry to address this issue and are researching deterrents for the poles near the nest and elsewhere.

Bob with Four

Eggs, eggs, eggs!

Egg Questions and Answers

How long does it take a bald eagle egg to hatch?
There are two ways to think about this: from egg laying to hatch, and from pip to hatch

• From egg-laying to hatch: Most experts say 35 days, give or take a few. In Decorah, hatches have ranged from 35 to 39 days after lay, with the first egg usually taking the longest. I'd look for first hatch to occur about 38 days after lay, so we're looking at March 28.  In Fort St. Vrain, hatches have ranged from 36 to 40 days after lay, with the first egg usually taking the longest, so we're looking at March 25th. But it could be a little earlier or a slightly later than that.
• From pip to hatch: Pipping occurs when the baby eagle's egg tooth first breaks through the eggshell. It can take as long as a day for the chick to fully hatch. 

How big is an eagle's egg?
Bald eagles lay white, oval shaped eggs. Size-wise, they are just a tad smaller than a tennis ball, although tennis balls are round, not oval. They weigh approximately 125 grams or 4.4 ounces, and are on average about 2.9 inches long and 2.2 inches wide.



How many eggs will the eagles lay? Will all of their eggs hatch?
Although the most common clutch size for eagles is two eggs, the Decorah Eagles and Fort St. Vrain  have a history of laying three eggs. The breakdown among bald eagles in general is as follows:

• 79% of clutches have two eggs
• 17% of clutches have one egg
• 4% of clutches have three eggs

Both sets of eagles have hatched all of their eggs to date; however, fertilized eggs can fail to develop due to extreme cold, soft shells, or microorganisms. We are hopeful they will have another great year, but we won't know until it happens.

What is in those eagle eggs?
At this point, the developing embryo is still quite small. It is surrounded by the amnion, a fluid-filled bag that helps protect it from jarring and sloshing. The yolk and albumin provide nourishment and additional cushioning, the allantois filters out waste products from the kidneys, and the chorion provides ventilation.  Inner and outer shell membranes help safeguard the embryo from bacterial contamination and keep the egg's insides from leaking out through its highly porous surface.  Embryo, fluids, and membranes are all enclosed in a chalky membrane that strengthens the egg, providing an additional layer of protection from punctures and pressure. An outer cuticle on the chalky membrane (what we think of as the shell) gives texture and even more protection to the eggs.

How do eagle parents care for eggs?
Eagle parents ensure optimal temperature and humidity by alternately incubating, getting off, and rearranging their eggs. While turning eggs might be a matter of instinct, it also prevents the embryos from sticking to the insides of their eggshells, and it optimizes membrane growth. They move very carefully around the eggs, often balling or partially closing their long, sharp talons to keep from puncturing the eggs. Concerned about the amount of time the eagles are spending off the eggs?
Read this blog: http://raptorresource.blogspot.com/2014/02/eggs-and-cold-weather.html

The following resources helped me learn and write about this topic:

• Bald eagle egg size and color:
  http://eaglenest.blogs.wm.edu/2010/02/04/bale-eagle-egg-size-and-color/
• What's inside that egg?
  http://eaglenest.blogs.wm.edu/2010/02/26/what-is-in-those-eagle-eggs/
• The importance of egg-turning:
  http://www.wqed.org/birdblog/2013/04/12/turning-the-eggs/
• Previous blogs at this site.

Did you know?

Some birds bury their eggs in compost heaps to incubate them. Meet the megapodes!
http://www.wqed.org/birdblog/2011/08/18/born-in-a-compost-heap/

Sex determination in birds

Humans, other mammals, and some insects genetically determine sex via X and Y chromosomes. In the XY sex-determination system, females inherit an X chromosome from each parent, while males inherit an X-chromosome from their mothers and a Y-chromosome from their fathers. Since homogametic XX females produce only X chromosomes, heterogametic XY males dictate the sex of their offspring.

Human watchers (including myself) often apply sex-based characteristics to our beloved eagles. Mom and Dad appear to have many of the same housekeeping arrangements and arguments that we do, so it might be surprising to learn that they turn our XY sex-determination system on its head!

Introducing...the ZW sex-determination system!
Birds, some reptiles, some amphibians, and some fish replace our X and Y with the ZW system. Let's look at a few differences:

• I'm a female homogametic XX and my husband is a male heterogametic XY, but female birds are heterogametic ZW and male birds are homogametic ZZ. Among other things, this means that Mom's ova determines the sex of the little E's (or D's) we coo over in Decorah and elsewhere. 
• XY and ZW chromosomes come from different areas of the genome. That means that our system for genetically determining sex is not very closely related to a ZW'er's system for determining sex, even though they both work roughly the same way. 
• ZW sex determination is dose-dependent, at least in birds. Z doesn't create a male in and of itself. Two Z's (ZZ) are required to make enough male-determining product. Females may be female not because of the W, but because they lack two Z's.

Having said that, ZW females still produce eggs and ZZ males still produce sperm. There are some other similarities between us and them:

• The non-recombining Y and W chromosomes have both degenerated over time. Today, the mammalian X carries over three times more genes than the Y does, whereas the chicken Z carries over ten times more than the W. Like our Y-chromosome, the W doesn't combine well with its opposite. Deletion, degradation, and mutations occur more quickly on the Y and W than on the X and Z. 
• Y and W resemble X and Z more closely in 'primitive' animals and plants than in those that have evolved more recently, and both Y and W continue to shrink. Will human maleness and bird femaleness disappear? I don't think it's likely, but some people believe that new forms of sex determination might arise from somewhere else in the genome.  

How does the ZW system affect birds?
We know birds aren't human, even though we might call them Mom and Dad, think of them as friends, and invest them with human-like feelings, duties, and housekeeping systems. Still, it seems odd that they have a system of genetically-determined sex that is so different than ours. How does the ZW system affect them? 

• Z chromosomes contain more genetic information than W chromosomes. Since ZZ male birds have two Z chromosomes, they are more likely to pass on sex-linked traits than ZW female birds. For example, Decorah daughter (ZW) Four got a Z from Dad and a W from Mom, while son (ZZ) Decorah got a Z from each parent. A male bird contributes a Z to sons and daughters, while a female passes a Z to sons only. Since Dad's Z contains a lot more information than Mom's W, Dad contributes more genetic information on that particular chromosome, especially when it comes to daughters. In humans, females conserve more sex-linked traits than males, and pass them on to male and female children. The opposite is true in birds. 
• What about that flashy male plumage? We know that male birds conserve more sex-linked traits and pass them on to sons and daughters, but male plumage is more complicated than it appears.  Recent work published in the journal Evolution indicates that female birds were once as flashy as males. We think that sexual selection drove male color evolution (females prefer colorful males), and natural selection drove female loss of color (brighter females and young were more likely to be spotted by predators and competitors). 
• So what role did the ZW system play? A couple of ideas. W has degraded over millions of years and carries much less information than it did previously. If the gene for female color was located on W, it may have been lost somewhere in the past. Alternatively, Z is more highly expressed than W. The resulting imbalance in hormonal secretions between lower ZW females and higher ZZ males drives fundamental sex differences in phenotype, development, and physiology. A ZW chromosome may not provide enough oomph to turn bright plumage on elsewhere in the genome, assuming it exists in female birds.
• What about birds of prey? Unlike most birds, female raptors or birds of prey are larger than male birds of prey. And unlike most birds, male and female raptors sport the same plumage. With the exception of kestrels, we can't use plumage color to tell males and females apart. What happened to de-link plumage color with sex and why is size, which is still linked to sex, inverse almost uniquely among birds of prey? Is it expressed in the Z or W chromosomes (W chromosomes are 'large in many raptors'), or elsewhere in the genome? Curious minds want to know!  

Why do we have XY and ZW?

No one knows for sure. All snakes and all birds use ZW determination, and all mammals use XY determination (even when it gets weird, as it does with platypus and voles, X is always present). But fish, amphibians, turtles, and lizards might use XY, ZW, or temperature-dependent selection (TDS) depending on the species. The switch from a variety of systems (ZW, TDS, XY) appears to have occurred around the time the ancestor of all reptiles split from the ancestor of all mammals, but it's not yet clear whether there was an intermediate stage between ZW and XY systems, or whether the transitions occurred directly.  

Is the ZW system really that different? I don't think so. While lovely heterogametic ZW Mom determines sex and handsome homogametic ZZ Dad passes more genetic material to his offspring, males still produce sperm, females still produce eggs, and genetically determined sexes are still differentiated by phenotype, development, and physiology. Whatever the reason for XY and ZW, us XY'ers at the Raptor Resource Project wish all birds the best of luck this spring!

A list of resources that helped me learn about this topic:

• http://io9.com/why-do-birds-have-zw-sex-chromosomes-instead-of-xy-1682328912. A well-written article!
• http://www.slideshare.net/GigaScience/graves-smbe-2014. A great slideshow on sexual determination systems.
• http://nothinginbiology.org/2014/11/17/sex-chromosomes-in-conflict/. How do we end up with complex XY systems? This article points a way.
• http://www.sciencedirect.com/science/article/pii/S0960982206019968. Relationships between vertebrate XY and ZW systems.
• Evolution of the Y-chromosome. http://www.hhmi.org/biointeractive/evolution-y-chromosome
• Sex determination: Why so many ways of doing it? http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001899. This is a long read.
• Factors causing sex differences in birds. Does anyone have aspirin or maybe a trashy novel to ameliorate all this information? A good article, despite my snark.
  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3864897/
• Drab female birds were once as bright as their mates:
  http://www.smithsonianmag.com/science-nature/drab-female-birds-were-once-flashy-their-male-mates-180951427

Did you know?

• One way the Y might disappear (if it did): http://science.kqed.org/quest/2008/07/07/why-no-y-gender-bending-transcaucasian-mole-voles/

Line-Up: Barred Owls, Great Horned Owls, and Bald Eagles

At A Glance
How do our birds compare? While bald eagles are clearly the heavyweights of the group, barred owls and great horned owls are territorial and can be quite aggressive. All three are generalist feeders. Bald eagles build stick nests, while barred owls and great horned owls nest opportunistically.

	Barred Owls	Great Horned Owls	Bald Eagles
Length
	16.9–19.7 in 43–50 cm	18.1–24.8 in 46–63 cm	28–37.8 in 71–96 cm
Wingspan
	39–43.3 in 99–110 cm	39.8–57.1 in 101–145 cm	80.3 in 204 cm
Weight
	1.03–2.3 lbs 470–1050 g	2.0–5.5 lbs  910–2500 g	6.6–13.8 lbs. 3000–6300 g
Diet
	Small mammals, birds, amphibians, reptiles, fish, and invertebrates.	Diet Small mammals, birds, amphibians, reptiles, fish, and invertebrates.	Fish, birds (especially waterfowl), small to relatively large mammals, reptiles, amphibians, crustaceans, and carrion.
Nests
	Lays eggs January to April (Iowa). Nests in cavities, other birds' nests, squirrels' nests, and nest boxes.	Lays in February (Iowa). Nests in other birds' nests, squirrels' nests, cavities, dead snags, deserted buildings, cliff ledges, and human made platforms.	Lays eggs mid-February to early March (Decorah). Builds large stick nests and nests in them for multiple years.
Habitat
	Mixed forests of large trees, preferably near water.	All over, although they have a preference for spaces that combine open habitat with forest.	Forests of large, mature trees adjacent to bodies of water

This line-up makes it pretty clear that the area is as desirable to owls as it is to eagles. Like much of the #driftless, the area encompasses forest, blufflands, running water, ponds, and open spaces. Food is abundant and nests and potential perching spaces abound.

We know how eagles and owls interact. But how do great horned owls and barred owls interact? It looks like great horned owls are a bigger problem for barred owls than they are for bald eagles. The good people at Cornell Lab of Ornithology write that ...A barred owl's most dangerous predator is the Great Horned Owl, which eats eggs, young birds, and occasionally adults. A video made by Dragonlainey on the night of February 3rd features the sounds of great horned and barred owls. It opens with great horned owl calling. Instead of the familar pair hooting, this sounds a bit more like a harnk call - another great horned owl call that isn't especially well-understood (this is a guess on my part and I will add more information if I get it). Familiar GHO hooting starts at about 1:05 into the video, and at about 3:15, we hear an unearthly noise that sounds a lot like the alarm call of barred owls as recorded at The Owl Pages.

• Great Horned Owl Vocalizations (note that several came from Karla):
  http://www.owlpages.com/owls.php?genus=Bubo&species=virginianus
• Barred Owl Vocalizations:
  http://www.owlpages.com/owls.php?genus=Strix&species=varia

Could the great horned owls displace the barred owls or vice versa? The jury is out on that question. Cornell writes that barred owls are...Territorial all year round, Barred Owls chase away intruders while hooting loudly. They are even more aggressive during nesting season (particularly the females), sometimes striking intruders with their feet. We've seen the barred owls attack the eagles in the nest before, and barred owls are displacing spotted owls in the northwestern United States, but I couldn't find any evidence of them displacing great horned owls. While Cornell mentions that great horned owls can shift barred owls on their range, I couldn't find any documentation of outright displacement there, either. I did learn that barred owls are real homebodies. In a study of 158 banded barred owls, researchers sound that none of them displaced more than about six miles away. Compare that to D1's 900+ mile odyssey, or even Four's 100-mile journey!

At present, I suspect the owls and eagles will live uneasily together in inter- and intra-order competition. If we can find and reach the barred owl nest, it would be interesting to band the young and study the family's movements now that great horned owls have arrived.

Additional Owl blogs from RRP

• 2014 - Owls in N2: http://goo.gl/glgEHx
• 2013 - Strigiformes (general information): http://goo.gl/hseHSD

Things that helped me learn about this topic

• Karla Bloem, International Owl Center, personal communication and website. The International Owl Center isn't far from Decorah, Iowa, for those of you planning trips. #Driftless #Owls #YouShouldVisit
• Cornell Lab of Ornithology on Barred Owls, Great Horned Owls, and Bald Eagles.
• The wonderful owl pages website. If you are an owl fan, check it out: http://www.owlpages.com/

Did you know?

• A barred owl is attacking joggers in Salem, Oregon: http://goo.gl/ABw1BP

How Do Bald Eagles Stay Warm In Cold Weather?

Mom, Dad, and eaglets in a late storm, 2011

We get a lot of questions about bald eagles and cold weather. I've written a few posts on the subject, but thought I'd combine them here. Unique body features and changes in physiology and behavior help bald eagles maximize energy gain, minimize energy loss, and incubate eggs in cold temperatures.

To maximize gain, eagles forage in groups, gorge food, and increase the assimilation of ingested food energy. To minimize loss, they become sedentary, seek protective microclimates, and reduce night-time body temperature. Put simply, successful eagles use the least amount of energy to get the most amount of food. Here's how they do it.

• Foraging in groups (or observing and following other birds on their territory) increases the likelihood that eagles will find food with less energy expenditure than if they hunted alone. Bald eagles steal prey from other eagles and birds (kleptoparasitism), an optimal behavior, at least during periods of food scarcity, for animals that forage together. 
• Gorging food helps eagles load calories quickly and reduces the likelihood of food theft by another animal.
• Cold weather causes changes in blood flow. Less blood flows to skin and extremities, making more blood available for visceral organs like the stomach.  This helps eagles reduce energy radiation and increase the assimilation of ingested food energy at a time when every calorie is crucial. 
• It takes energy to fly, procure sticks, and nestorate. Reducing activity reduces energy consumption and slows metabolism.
• Sheltering in protective microclimates (thick brush, bluff pockets, sheltered branches, coniferous trees) reduces wind exposure. These microclimes also holds heat more efficiently than open spaces, slowing energy radiation and minimizing loss. 
• Bald eagles reduce their body temperatures at night an average of 1.8 degrees. This slight hypothermic condition reduces the temperature gradient between their body and the environment, letting them burn fewer calories to stay warm. 

Eagles also have physical adaptations that help them stay warm and incubate their eggs. 

• Feathers are wonderful insulators. The roughly 7,000 feathers an eagle grows help keep it warm and dry. Stiff exterior vane feathers zip together over smaller, fluffier down feathers, providing an overcoat of sorts to shed water and help keep heat from escaping. Underneath, down feathers trap pockets of air next to the eagle's body, where it is quickly warmed and prevented from escaping. 
• However, some heat needs to escape during incubation. A brood patch is a patch of bare skin on an eagle's breast. Eagles can roll, wiggle, and tuck their eggs up against the brood patch, effectively transferring heat from the eagle's roughly 104-degree body to the eggs. Since the optimal temperature for incubation is 99 degrees, some heat can be lost. The eagles regulate egg temperature by alternately incubating the eggs and leaving them uncovered. 
• An eagle's large size helps it retain heat. Eagles have a higher inside-to-surface area ratio than a smaller bird like a chickadee. Less surface area means less heat lost to radiation, which is why, within a broadly distributed group of animals, northern animals tend to be larger than their southern cousins. (http://en.wikipedia.org/wiki/Bergmann%27s_rule)
• An eagle's legs use counter-current heat exchange to control body temperature. Warm arterial blood flowing from an eagle's core into its feet passes cool venous blood flowing the other way. Heat is exchanged, warming the blood flowing into its core and cooling the blood flowing into its feet. The cooler blood is still warm enough to prevent frostbite, but the lower temperature reduces the gradient between its insides and its outsides, preventing excessive heat loss through its feet. 
• An eagle's leg muscles are tucked up under its feathers, nearer the warm center of its body, and it has very few soft tissues in its long legs and feet, which are wrapped by thick, scaly skin that helps protect them from the cold. If its feet do get cold, it can always tuck them, often one at a time, underneath its feathers. 

It's hard not to be concerned about eagles and other wildlife during extreme cold events. But eagles and other animals that live outdoors are well-prepared to deal with them. You can help by keeping seed and suet feeders stocked, keeping water available, and providing shelter for birds. The Minnesota DNR offers these winter feeding tips. http://goo.gl/KRqbrv. Our pinterest has some cute ideas, with more to come: http://goo.gl/O4eXWx 

More information on Eagles and Cold

• Feather and Weathers: http://goo.gl/46BZmA
• Eagles and Cold: http://goo.gl/Bp2Rfy
• Eggs and Cold: http://goo.gl/AJysIZ

References

Ecological Energetics and Foraging Behavior of Overwintering Bald Eagles

Mark V. Stalmaster and James A. Gessaman

Ecological Monographs

Vol. 54, No. 4 (Dec., 1984), pp. 407-428

Published by: Ecological Society of America

Article Stable URL: http://www.jstor.org/stable/1942594

Food Consumption and Energy Requirements of Captive Bald Eagles

Mark V. Stalmaster and James A. Gessaman

The Journal of Wildlife Management , Vol. 46, No. 3 (Jul., 1982) , pp. 646-654

Published by: Wiley on behalf of the Wildlife Society

Article Stable URL: http://www.jstor.org/stable/3808555

Ask A Naturalist: Why Don't Duck Feet Freeze?
http://askanaturalist.com/why-don%E2%80%99t-ducks%E2%80%99-feet-freeze/

A Great Read

Winter World: The Ingenuity of Animal Survival by Bernd Heinrich

Did you Know?

Temperature Rhythms Keep (Human) Body Clocks in Sync: http://www.sciencedaily.com/releases/2010/10/101014144314.htm

Kleptoparasitism: http://en.wikipedia.org/wiki/Kleptoparasitism