Body plans and BOP shapes

Since we are watching bald eagles and peregrine falcons, I wanted to talk a little bit about body plans and their influence on flight, hunting, and prey base. As watchers know, eagles are soaring generalist hunters that eat almost anything they can sink their talons into, while peregrine falcons are energetic, acrobatic flyers that specialize in catching birds in the air. Both are birds of prey, but their body plans and wing shapes result in very different lives.

Body plans, size, and flight
With their long, broad, slightly rounded wings, large wing slots, and broad, wedge-shaped tails, bald eagles are built for soaring. They hold their wings flat and save aerial acrobatics for hunting and encounters with other birds. While tail winds and thermals aren’t absolutely necessary for eagle flight, their migration corridors and styles take advantage of both. Thermal winds are powered by sunlight, which means that eagles migrate during the day. They also tend to prefer wind corridors, including ridgelines and funnels that concentrate and amplify wind – think of the cliffs of the Mississippi river or the tight river valleys and ridges of NE Iowa. A stiff tail wind will send migrating eagles aloft in their thousands, especially over surfaces with little opportunity for thermal soaring. The Bald eagle body plan and low-aspect wings - large, broad wings relative to its overall surface area - is most suited to low-angle, low-energy soaring flight.

Unlike bald eagles, Peregrine falcons are built for speed and maneuverability. They have long, narrow, pointed wings and long tails shaped for diving, twisting, and turning in flight. Where eagle flight is flat, peregrines often fly in a series of arcs as they dive, dash and pursue other birds in flight. The peregrine body plan and high-aspect wings - narrow, pointed wings relative to its overall surface area - is most suited to high speed, energetic and often acrobatic powered flight.

Bald eagle silhouette

Peregrine falcon silhouette

Although I don't confuse falcons and bald eagles, I often find body plan and flight style to be very helpful in identifying similarly-sized birds of prey at a distance. Is it large and flying flat, holding its wings in a vee and tilting as it flies, or M-shaped? If you are in northeastern Iowa, the first is probably an eagle, the second is probably a turkey vulture, and the third is probably an osprey. Are the wings large or small in proportion to the rest of the bird? Are its wings pointed or rounded? Is its tail long or wedge-shaped?  Is it flapping and gliding, diving, hovering, or quartering low over a field? Did you see it in the woods or in the open? Body plan, behavior, and habitat are very helpful in identifying birds of prey, especially at a distance.

Silhouettes of birds of prey in flight from learner.org: http://www.learner.org/jnorth/tm/HawkPrimer.html

Body plans, hunting, and prey base
In general, all birds of prey have keen vision, talons, and curved beaks to help them hunt, kill, and eat prey. But not all beaks, talons, and hunting styles are the same. The peregrine falcon’s speed and maneuverability makes it uniquely suited to catching birds in flight, while a bald eagle’s size, strength, powerful feet, and long talons make it an excellent generalist hunter. Both birds take full advantage of their very different body plans when it comes to catching and eating prey.

A peregrine's high speed, high angle dive

A bald eagle's lower speed, lower angle flight

A peregrine falcon’s speed and maneuverability allow it to fly high, dive steeply, and hit prey so hard that the force of impact severs its prey’s spinal cord. A peregrine begins its dive by rolling, cupping its wings around its body, and tucking in its feet, yielding an aerodynamic raindrop that slices through the air at high speeds.  Special cone-shaped bones in its nostrils – an adaptation unique to peregrine falcons – allow it to breath while diving at speeds of over 200 miles per hour.  As the falcon approaches its prey, it extends its feet, brakes sharply, and snatches it out of the air with its long, slender toes and sharp talons. If hitting a bird doesn’t kill it, peregrine falcons use their tomial tooth – a special notch in their beaks that bald eagles don’t have – to sever their prey’s spine. While a peregrine’s feet are strong and quick – great for grabbing and slashing attacks – they don’t have the crushing strength of a bald eagle and their diet is largely restricted to other birds. 

A bald eagle’s large size, soaring flight, and strong feet help it to take a wide variety of prey, although its speed of attack is slower, its angle of attack is lower, and it usually kills prey with its feet. As we’ve seen at the fish hatchery, Mom and Dad swoop shallowly over the retaining pond, braking heavily as they plunge their feet into the water and pull out trout. Without stopping, they fly into a tree, on to the bluff, or into the nest, crushing or stabbing the trout with their powerful feet and sharp talons. Although they have special adaptations called spicules – rough bumps that help them grip slippery fish - bald eagles don’t specialize in any one kind of prey, and their size, strength, powerful feet, and fishing ability give them access to an extremely wide prey base.

Again, falcons and eagles are very different and I don't confuse the two, even at a distance. But understanding how body plans influence birds is useful to understanding their lives and identifying them in the field. I find it to be more helpful overall than looking for hard to see features, especially if a bird is far away. 

Hashtag #musing: could body plans impact gregariousness? Off their breeding grounds, bald eagles are quite gregarious. Their flashy colors, large, visible body plans, and wind-seeking behavior often bring them into proximity with other eagles. Eagles compete (think piracy and kleptoparasitism) but they also eat a wide variety of prey and often benefit from following other eagles when searching for food. As far as we know, peregrine falcons are loners. During migration or following dispersal, there can be multiple peregrines in a site with an abundance of food. However, they aren’t gregarious. Perhaps their more solitary behavior is driven in part by a body plan that results in a restricted prey base (leading to serious food competition), no real benefit to stealing or attempting to steal food, and less congregation around important dynamic and thermal soaring points.

Did you know?
A turkey vulture "V" is more correctly referred to as a dihedral. Turkey vultures are masters of soaring without flapping as they ride the wind in search of carrion. How do they do it? As wind strikes one wing or another, tipping the vulture right or left, one wing tips high and the other tips low. Wind flows under the low wing, pushing the vulture and righting it until it tips again. This allows them to exploit the smallest of air currents as they soar lowly and slowly through the sky. While they sacrifice some maneuverability, their food - carrion - doesn't require agility to catch.

Harriers also engage in dihedral flight, but their food - small mammals, reptiles, amphibians, and birds - requires considerably more agility. Compare their body plan with that of a turkey vulture. Dihedral flight allows them to soar very slow and very low, but they have a long tail and wings more like a falcon, which helps them roll and twist when needed. Harriers are a very interesting bird of prey: visit Cornell's website to learn more about them! https://www.allaboutbirds.org/guide/Northern_Harrier/lifehistory

And finally, I've seen some interesting conundrums when people compare birds to aircraft. Remember that aircraft can't change their shape to respond to wind conditions or the need to rapidly change position. But birds can and often do change shape as they fly! I chose silhouettes that I thought best represented each bird overall, but birds might adopt different flying styles under different conditions, even if they can't change their overall body plan.

Things that helped me learn about this topic

• Watching birds. Read, learn and apply in the field! There is nothing like a few hours of playing 'turkey vulture or bald eagle' in Decorah to hone your ID skills!
• Migrating Raptors of the World. I'm putting in a link but I also own a hard copy of this book. I recommend it for anyone who wants to learn more on the subject: http://bit.ly/2mUoDON
• How birds fly: https://www.sciencelearn.org.nz/resources/303-how-birds-fly
• Nature's flyers: http://bit.ly/2n7gIhY
• Thermal soaring: https://www.aviationweather.ws/095_Thermal_Soaring.php
• Wingspan curriculum activities
• Dihedral flight: http://www.boldmethod.com/learn-to-fly/aerodynamics/why-your-wings-are-tilted-up-dihedral/
• Northern harrier: https://www.allaboutbirds.org/guide/Northern_Harrier/id
• Turkey vulture: https://www.allaboutbirds.org/guide/turkey_vulture/lifehistory
• And finally, a very tricky ID! http://feederwatch.org/learn/tricky-bird-ids/coopers-hawk-and-sharp-shinned-hawk/

Endangered Species Act Under Threat From Congress

"When the last individual of a race of living things breathes no more, another Heaven and another Earth must pass before such a one can be again" - William Beebe

Dad Decorah near N2B

What is the Endangered Species Act? Signed into law by President Nixon in 1973, the ESA is the strongest and most important federal law protecting imperiled wildlife and plants. It has prevented hundreds of species from going extinct since it was enacted. Do you enjoy watching Mom and Dad Decorah or any other eagle families? Although they are no longer endangered - protections under the Act are supposed to recover species - the banning of DDT and the passage of the Endangered Species Act was critical to their survival.

Now the Endangered Species Act is under threat from some members of Congress, who see a chance to roll back its influence. “It has never been used for the rehabilitation of species. It’s been used for control of the land,” said House Natural Resources Committee Chairman Rob Bishop. “We’ve missed the entire purpose of the Endangered Species Act. It has been hijacked.”

Bald eagles, peregrine falcons, brown pelicans, California condors, whooping cranes, Puerto Rican parrots, and spotted owls beg to differ with Congressman Bishop's assessment, as do grizzly bears, several species of whales, southern resident orcas, sea otters, gray wolves, and manatees. Unfortunately, recently extinct Carolina parakeets, ivory-billed woodpeckers, passenger pigeons, eskimo curlews, and dusky seaside sparrows are gone forever and thus unavailable for comment.

Peregrine falcon at Xcel Blackdog power plant

I had the privilege of visiting Chicago's Field Museum during a peregrine conference three years ago. Attendees were given a behind-the-scenes tour of the museum, including a look at their vast bird collection - lovingly preserved corpses of birds kept for study and remembrance. It was there that I got my only look at the Carolina parakeet and the ivory-billed woodpecker. Gone forever from life, the two species now exist only as study skins in museums. Had the United States not banned DDT and passed the Endangered Species Act, it is highly likely that peregrine falcons, bald eagles, and many other animals would have joined them, existing only as museum specimens and curiosities on film. However cherished their memories or lovingly preserved their corpses, they too would be gone, dead, extinct, lost. Forever.

Imagine life without them. I can't stand the thought.

Looking for proof of the Act's success? The Center for Biodiversity conducted an exhaustive analysis of bird recovery under the Endangered Species Act and found it has been extraordinarily successful in recovering imperiled birds. Eighty-five percent of bird populations in the continental United States increased or stabilized while protected by the Act, and the average population increase was 624 percent. It was believed that listed bird populations would need 63 years to recover, but several populations (including bald eagles and peregrine falcons) have recovered far more rapidly than expected. As mentioned earlier, peregrine falcons and bald eagles have both been removed from the list.

Dan Berger's notes. All of the Peregrines east of the Mississippi in the
surveys he made in the 1950s and early '60s. Not an exaggeration...this was it.

Habitat/land has long been part of the argument against the Endangered Species Act. Those who oppose the act tend to cite the subjection of humans to land use regulation; the restriction of activities like farming, lumbering, construction, and mining, and the lack of compensation to landowners impacted by endangered species. But there are also many untruths in their arguments. Contrary to their arguments:

• The Endangered Species Act has recovered species.
• Landowners won't lose their homes because an endangered species is on their property. 
• Conservation groups and biologists do not just want money from the federal government. Folks, I have to tell you - conservation is the wrong field if your goal is money!
• It does not kill jobs. Section 7 of the US Endangered Species Act (ESA) directs federal agencies to help conserve listed species. One way it does this is by requiring agencies to consult with the US Fish and Wildlife Service and National Marine Fisheries Service to ensure that proposed federal actions won’t threaten a listed species’ survival. Between 2008 and 2015, 81,461 projects advanced without protections for wildlife, 6,382 advanced requiring only minor modifications for wildlife, 2 advanced requiring protections, and 0 were stopped. This seems to indicate that ESA could work even more effectively than it does now.

I don't understand the argument against preserving habitat. Animals can't live without it and so much is already gone. Why is it considered bad to preserve the 10% of Iowa that isn't under till? Or the Boundary Waters Canoe Area, which covers just 1.9% of Minnesota's total area? Does it really all need to be mined, timbered, and torn up for profit?

I believe in public/private collaborations such as ours and this shining example - how could I not, with what Bob called our 'unique marriage between industry and conservation'? I've seen the power that these relationships can have to secure habitat, change perceptions, and help species. But legislation and enforcement are also necessary, and the reforms being proposed right now are aimed at the destruction of the Act, not its betterment. For the sake of the birds we watch and love, please stand up and say "No" to any attempts to weaken or repeal the Endangered Species Act. We will be following and blogging on this issue and the issue of public land transfer.

Things you can do:

• Sign a petition that the American Bird Conservancy will take to Congress. We signed and it endorsed it organizationally, the first time we have done so: http://bit.ly/2k9o2YL
• Contact your representative. Follow this link for contact information: http://www.house.gov/representatives/find/. 
• Contact your senator. Follow this link for contact information: https://www.senate.gov/senators/contact/

You are welcome to take anything from this blog and re-use it in a letter, email, or editorial. Keep your tone respectful and remember that conservation is not and should not be a partisan issue.  But please comment! Bob always believed that we can make a difference. Let's prove him right.

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Resources

• Scientific American: The five biggest myths about the endangered species act
• Live Science: Ten animals back from the brink
• The Effectiveness of the Endangered Species Act: A Quantitative Analysis
• A wild success: A systematic review of bird recovery under the Endangered Species Act
• Study on federal projects and the ESA: http://www.pnas.org/content/112/52/15844.full.pdf
• Section Seven Explorer: https://defenders-esc.shinyapps.io/section7/
• WaPo article on the Endangered Species act and jobs
• Scientific American's Extinction Countdown Blog
• I didn't use it in this blog, but Rachel Carson's book Silent Spring is perhaps more relevant than ever with the decline of bees due to neonictinoid pesticides.

Public land is understandably a far hotter issue in the western United States, where the federal government owns vast tracts of land. But even there, groups like Sportsmen's Access, Backcountry Hunters and Anglers, and the Theodore Roosevelt Conservation Partnership are fighting for public land. I get upset email on our support for hunting and fishing, but I encourage people to take a look at what these groups and others like them are doing to support public lands. They are also an important reminder that conservation isn't, in the words of the Theodore Roosevelt Partnership, red or blue.

It has also been pointed out to me that bald eagles and peregrine falcons live pretty comfortably with humans. But not all species can live as comfortably with humans as bald eagles and peregrine falcons do. Do species that can't matter less than those that can?

And finally, the struggle to preserve wildlife and wildland is, in my opinion, an absolute necessity for our own survival. If they don't make it, we won't either. We aren't an exception to the requirements of clean air, clean water, and habitat, and humans and animals are in this glorious, lovely mess called life together.

Where do falcons and eagles go in winter?

Lately I've been getting asked where our falcons go to winter. The answer is complex. Birds do not fly south simply to escape the cold. Snow and ice seal the food supply and/or habitat of many birds away until spring: hummingbirds don't have flowers, waterfowl don't have water, and most insectivores don't have insects. However, peregrine falcons and bald eagles are able to weather winter since their food supply remains locally abundant, or at least present, year-round. Both species are partial migrators: that is, some birds migrate and others don't.

Bald eagles eat a wide variety of food, including other birds, mammals, reptiles, and invertebrates. They take their food live, freshly killed, frozen and left in the nest, or as carrion, and they can gorge food quickly and fast for days if need be. Peregrine falcons eat almost solely other birds they catch in flight, but many birds winter in Minnesota and Iowa, especially in cities and along open stretches of water. While there has historically been some natural open water along the Mississippi river during the winter (Eagle Valley, for example), the number of open water spots has increased with industrialization. Power plants discharge warm water that keeps stretches of rivers and lakes ice-free, providing spots for birds like swans and geese to winter (especially when people feed them, as they do here). Cities and industrial sites provide food and shelter for non-migratory birds like rock doves, which builds populations and makes wintering in place much easier. Even in the harshest winter, falcons and eagles have ample access to food in places like Minneapolis, St. Paul, Bayport, Decorah, Red Wing, and even northerly Duluth. 

Even with ample access to food, our winter weather is pretty gnarly. Birds have wings, so why don't they leave? We don't know for sure, but we do know that migration is costly and risky, and a good territory is hard to find. Falcons and eagles that stay on site have an advantage against territorial interlopers and are less likely to find themselves replaced by another mate come springtime. Years of occupancy on site yield a deep map of the the territory - places to find food, niches to shelter, and a knowledge of the local fauna - that helps animals survive even under adverse conditions (see this blog for more information about how eagles handle winter). 

So I've talked about peregrines and eagles that stay, but what about peregrines and eagles that leave? Transmitter studies indicate that mates don't migrate or spend time together off their breeding grounds. Among falcons and eagles, young don't migrate with parents, and we don't think they spend much time together after they disperse. 

Bald eagles tolerate - maybe even like? - cold. Many eagles that migrate don't fly into latitudes free of ice and snow. Eagles in central Canada might shift south as far as the Mississippi river in Minnesota, Iowa, and Wisconsin. Alaskan eagles go west to the sea. Eagles in central north America might fly to an open body of water not too distant from their breeding grounds, joining winter eagle congregations in places like Eagle Valley, Wisconsin; Clinton, Iowa (Eagle Point Park); Bayport, Minnesota (south of Xcel Energy's Allen S. King plant); and many other places.

Peregrine Falcon Migration Map

Peregrine falcons have been documented traveling a bit further south. We've had band returns from south Florida, an oil rig in the Gulf of Mexico, and Costa Rica (click these links to read about Island Girl and Immaculata). Thousands of Tundra peregrines have been trapped and banded at the Padre Islands in south Texas as they fly from an area up above the arctic circle to Central and South America - a distance of up to 15,500 miles! Florida reported a world record number of migrating peregrines just last week - an amazing 1506 in a single day count! 

In short, migratory eagles from Minnesota, Iowa, and Wisconsin might easily be wintering fairly close to home, spending time on open stretches of water along large rivers with eagles from central Canada who flew several hundred or a few thousand miles to get there. D1, D14, and Four all wintered in NE Iowa and (in D1's case) SE Minnesota (explore the cluster map for details). However, peregrine falcons from the same area might fly thousands of miles south to warm their feathers in Central and South America before returning to our area in late February and early March. 

The whole question of photoperiod length becomes even more interesting when migration is factored in. In late February, our latitude gets around 11 hours of sunlight daily. We peak on June 21, at 15 hours, 36 minutes. Non-migratory birds and Canadian migrants to our area also experience the shortest day, at 8 hours and 46 minutes on December 21. Falcons that migrate to Costa Rica experience a different photo-year than their non-migratory counterparts, however. A falcon that left on October 1 has a shortest day-length of around 11 hours. Its days will get slightly longer as it wings south. The shortest day in October in Costa Rica is 11 hours and 46 minutes long. The shortest day of the year is 11 hours and 32 minutes long. These birds have more average daylight over the course of the year, and a much flatter photo period map during the time they spend near the equator. The difference is even greater for birds like the Tundrius falcon, which summers at and above the arctic circle.

Some things that helped me write this post: 

• Mandernack satellite telemetry study: http://www.bioone.org/doi/abs/10.3356/JRR-10-77.1
• The Peregrine Falcon Research Group study: http://www.frg.org/SC_PEFA.htm
• Time and Date: http://www.timeanddate.com/

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

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.

Avian Parasites

On May 22, 2013, the falcon eggs at Xcel Energy's Blackdog nest box began hatching. Immature female 16/U laid four eggs and hatched three. Although both parents diligently cared for their young, they never seemed to thrive. On May 27th, a watcher reporter strange black patches on one of the young. By May 31, two of the three young were dead. We don't know how the first one was disposed of, but the parents fed the second young to the third.

In watching the box, we noticed the strange black patches. We also saw that the remaining baby didn't seem to be developing properly. It was quite small for ten days of age, spent more time under its mother than might be expected, and didn't seem to be developing feathers properly. Perhaps the young falcon had Frounce, a yeast infection of the digestive tract that interferes with food intake. We decided to go up the stack and treat it with Spartrix. This has been a very hard year on our falcons and we really didn't want to lose any more.

I called Dan, our contact at the plant, and made the necessary arrangements. The Blackdog nest isn't especially easy to get to, since it is at the 600' level of the plant's smokestack. An elevator takes you to the 300' level and ladders take you the rest of the way. All told, you need to plan on a minimum of 50 minutes to visit the box. A big thanks to Dan for taking the time out of his day!

I was really shocked when we finally got to the nest. The falcon was very small, coated with black gunk, and swarming with parasites. They were on its back, belly, under wings, and neck. We thought the black gunk might be prey remains, but it was actually scabs, dried blood, and damaged feathers. The parasites,  probably Amblycera or Hippoboscidae, were feeding by chewing soft areas of skin, causing an area of localized bleeding from which they drank.

I decided to give the young falcon Spartrix just in case (Frounce could easily kill a falcon this stressed), and then Dan held the falcon while I carefully cleaned it off.

This is a closeup of the falcon's back and neck. The parasites caused extensive damage, destroying feathers,  interfering with feather growth, and delaying development. I killed and swabbed and crushed and killed and swabbed and crushed again. Once the parasites seemed to be (mostly) dead, I checked the box for anything that might be harboring more, took a few bits out, and returned the baby falcon, along with a dead quail. Mom was back in the box before we were back in the stack, and the quail was gone by the time we reached the bottom. Despite the damage, the young falcon had a good crop and even seemed somewhat feisty, weakly footing with tiny talons. While I don't know that the falcon will survive, we increased its chances of survival.

The parents have been very busy preening the young falcon, sometimes what seemed (to human watchers) rather roughly. We now know that they were trying to remove parasites. But where did the parasites come from? Since lice are transmitted by direct contact, I'm guessing that the lice were brought in on a prey item. According to Science Direct: "With no wings and very small eyes, chewing lice are, by and large, helpless away from their host." However, they were presumably able to hop, skittle, or jump from prey on to the young birds, who lack the armoring feathers of adults and weren't yet preening themselves. We'll be watching this box closely over the next couple of days to see what happens to the young bird.

Ever feel like a tick was crawling on you? Hours later, and I can still feel the lice crawling...

Peregrine Survey

Young falcons at Aggie's Bluff in 2012

According to the weather forecast, 4/16/13 was the only sunny day this week. Time for a peregrine survey! Dave Kester and I set off at 6:30 AM for the Lansing Power plant cliff, where we quickly located two adult falcons.  One was sitting on a cliff nest box that we mounted several years ago to attract falcons away from a ledge that provided poor shelter and was accessible to raccoon. The ledge nest site failed to produce young, but the nest box has proven productive. Nine young have fledged from this site since 2009.

We were very pleased to find an adult female falcon on Guider’s Bluff just south of the town of Lansing, IA.  We heard one bird wailing, indicating that there was probably a second falcon on site.

We did not find any falcons on Aggie's Bluff, two miles upstream of the Lansing, IA bridge.  We decided to head upstream and return to this cliff later in the day.
 
We found two adult falcons at the Shellhorn cliff just south of Brownsville, MN.
 
We did not stop for long at the new V cliff south of Homer, MN, since I had confirmed two falcons defending the site on my last river survey.  I remember hovering over this cliff ten or more years ago in a Bell Jet Ranger helicopter and thinking that someday this cliff could attract falcons, since it looks much more falcon-friendly from the air than from the ground.
 

Dan Berger at Homer Bluff. Dan documented
the extirpation of the Peregrine from the Mississippi
in the 1950s. He is still banding birds today. 

We were very excited to find two falcons defending the Homer/P4 cliff that has not attracted nesting falcons for a few years.  We observed one falcon fly and land in a tree very close to the eyrie location.
 
We have falcons at Red Wing Grain, but needed to confirm whether we also had them at Diamond Bluff, in Diamond Bluff Wisconsin. We were pleased to find two adult falcons defending this cliff, but we don't know whether they are using a nestbox or a pothole. This cliff will need some observation. We mounted this nest box over 20 years ago, and we are very pleased with how it has held up.

We saw falcons at West Bluff and Maiden Rock, staying at Maiden long enough to confirm one falcon protesting a vulture flying to close to the eyrie. All appears well at this location!

There were no falcons at Twin Bluff in Nelson Wisconsin. This is our third visit to this cliff without finding falcons, although we found two adults on our first survey. A mystery.
 
We found one falcon on the cliff face at Maassen's bluff, and our friends who live down below indicate that all is well.  The pair is using an eyrie we improved by adding 80 pounds of pea-gravel to improve nest drainage.

I observed one falcon at Castle Rock on 4/9/13, during driving rain.  On this visit, we observed two adult falcons. However, the adult female left the cliff and flew out of sight, heading directly north. She did not return. The adult male set off in the direction of the Bay State Milling plant in Winona, MN, where our nestbox camera has confirmed four eggs.  If I recall correctly, every time we have falcons at Bay State Milling we do not have nesting falcons at the nearby Castle Rock cliff.
 
We passed by the Homer/P4 cliff again and made our way downstream to a new cliff.  The light was very poor, since we had to look into the setting sun, but we did spot one falcon perched on a limb near the cliff top. We raced back up to the Homer (P4) cliff hoping to confirm falcons were not just bouncing back and forth between the two cliffs.  We were pleased to find two adult falcons on site.
 
 By this time it was getting late in the afternoon, and we wanted to return to Aggie’s Bluff to see if a second visit would lead to finding a falcon. Despite the poor lighting conditions, we were pleased to find one falcon perched on the cliff face.
 
We returned home at 6PM, pleased to finding so many falcons defending Mississippi cliffs.  It was not that many years ago that some thought we would never have the peregrine back on these historic cliffs. It is wonderful to see them back 30 years after my first captive bred falcon was released in the river valley.
 
Bob Anderson

Where Did That Falcon Come From?

Screen shot of the online banding info database

Yesterday, facebook user Jeff Suggs asked if any of the falcons we watch have Australian roots. The short answer is 'No'. As far as we know, none of the falcons we watch can trace their ancestry back to falcons imported from Australia for North American captive breeding and release programs. Having said that, the Peregrine Fund did include Australian Falcons (Falco peregrinus macropus) in the breeding stock they used to produce falcons for release.

To quote Captive Breeding and Releases of Peregrines (Falco peregrinus) in North America:

"Breeding projects were stocked with birds from many locations. The CWS Wainwright facility had birds taken from the wild as nestlings from northern and southern Alberta, the Yukon, and the Northwest Territories, Canada; the McGill facility had birds from northern Quebec. The Peregrine Fund at Cornell University had birds taken as nestlings from Alaska, Scotland, Australia and other places, while the Fort Collins facility had mainly birds from the Rocky Mountain region. Most of the birds at the SCPBRG were from California."

From what I was able to find, most of those falcons were released in the eastern United States. The use of non-native stock was quite controversial, as chronicled in the wonderful book Peregrine Falcon: Stories of the Blue Meanie by Jim Enderson.

So how do we find out where birds come from? I like to use the online Midwest Peregrine Falcon Database, which is maintained by the Midwest Peregrine Society and the Raptor Center at the University of Minnesota. Take 11/X, the immature female at Great River Energy. To look up her band number, follow the link below and enter 11/X in the number field of the color band info category. If you have a band color, select it from the dropdown to narrow your search. Most of our birds are either black over green or black over red.

The Midwest Peregrine Falcon Database: http://www.midwestperegrine.org/db/

It turns out that 11/X is MaryEllen, a 2012 hatch from Queen's Bluff in Winona County, Minnesota. Since both of her parents are known, I can trace her ancestry through them. MaryEllen's mother has FWS band number 1807-77654. By entering that number into the FWS field, I learn that her name was Jean. Jean was produced at Maiden Rock in 2001, the first year there were birds on that cliff, and banded by Bob.Jean's mother was the unnamed 1807-61966, who was produced at Firstar Bank in Cedar Rapids, Iowa, in 1999. Her mother 1807-29469 was captively produced by breeder and falconer Pete Widener and hacked from Des Moines Iowa in 1991.

Now for the Dads. MaryEllen's father was Cranberry 816-38602, produced at the Dairyland Power Alma plant in 2004. Bob also banded this bird. I remember it well, since we had to rush up the stack in between thunderstorms to get the young falcons. His father 2206-62744 was produced at Firstar Bank in Cedar Rapids, Iowa in 2000. His father 2206-13875 was produced by breeder and falconer Bruce Haak, a friend of Bob's, and also hacked from Des Moines, Iowa, in 1991. MaryEllen's parents are related through grandfather 2206-13875, who was present at Cedar Rapids in 1999 and 2000.

Thanks to bands and bird banders, the North American peregrine falcon is probably the most-documented bird population in the world. As I said in another post, if you see a band number, please post it here or on our forum. We love to know who we are watching!

To learn more about banding, follow these links:

• Bird Banding History
• How We Band: Reporting Bands

Jean's mate Gunnar was a bird produced and released by the Raptor Resource Project at Effigy Mounds in 1999. We'll be writing more about that project later this year. 

Peregrine Falcon Courtship

We are starting to see courtship at a number of peregrine nests. Those of you who watched at last year might remember that the falcons were in full laying mode by the first week of April. The cold spring seems to have pushed nesting activities just a little farther back this year, since by the last week of March 2012 we already had peregrine eggs at three nests.

The falcons begin with ledge and cliff displays, bowing and calling loudly. The male brings gifts of food to the female, often engaging in acrobatic mid-air food transfers. As courtship progresses, the falcons build a scrape for their eggs, digging into the gravel with their breasts and pushing to create a scrape. The male may solicit the female by bowing and e-chupping. Finally, both falcons bow and e-chup over the scrape.

GSBDweller caught Travis bringing Michelle food on Tuesday. We'll be watching closely for courtship activities at Great Spirit Bluff.

Michelle, Travis, and Peregrine Questions

Michelle and Travis hatched two young falcons on 5/13/12, and the questions are already flying! I'll try to answer a few of the most common here.

1. Why are they nesting in gravel? I wish the hatchlings had grass or something softer!
Historically, peregrine falcons nested in two places: on cliffs and in trees. To quote: "Although the peregrine falcon is currently considered a cliff-nester, records indicate that it once nested in tree cavities (Goss 1878, Ridgway 1889, Ganier 1932, Bellrose 1938, Spofford 1942, 1943, 1945, 1947, Peterson 1948). The peregrine still uses cavities in broken-off trunks in Europe (Hickey 1942), but the hole-nesting population of America apparently disappeared with the felling of the great trees on which they depended (Hickey and Anderson 1969)."

Either way, peregrines did not build nests out of branches, twigs, or grasses. Cliff nesting birds use ledges or potholes. These commonly have some kind of substrate: sand, pebbles, dirt, and so on. The male and female dig and wiggle out a scrape, or shallow cavity, into which the female lays her eggs. The substrate provides drainage, cups the eggs, and helps keep them from breaking on the edges of the underlying rock. We use 80 pounds of pea gravel in our nest boxes to simulate a substrate and protect the eggs.

2. How long can the babies go without eating?
The hatchlings consume the egg yolk shortly before hatching, which gives them enough nutrition  for 24 to 48 hours. However, they don't usually have to go very long. Their first feeding was at 11:49am CST this morning.

3. What do falcons eat?  Falcons eat other birds. We've found the remains of pigeons, woodpeckers, coots, finches, blackbirds, ducks, cuckoos, and many other birds stashed in and around nests. In general, the adults catch a bird by diving or stooping on it. If the impact doesn't kill it, the adults use their tomial tooth - a notch in their beaks - to bite through their prey's cervical vertebrae. They pluck their prey prior to eating: "feather falls" have helped me locate Peregrine falcons at the Mayo Clinic and the Dairyland Alma power plant. 

Adult peregrine falcons eat about 2 1/2 ounces (70 grams) of food per day. Using a rough back-of-the-envelope calculation, males average 587 grams of weight and females average 1205. So males eat roughly 11% of their body weight each day. I'm guessing - and this is a guess - that females do the same, so Michelle probably eats a little more than Travis does. It has been speculated that  gender-based size differences allow male and female birds of prey to eat from a slightly different prey bases, widening the available food supply.

So based on this calculation, I'd need to eat about 16.5 pounds of food every day to keep up with Michelle.

4. How fast will the babies grow?
Peregrine falcons double their birth weight in 6 days, and are 10 times hatch weight in three weeks.
Like the eaglets, they start with a fluffy white coat of baby down. We'll start to see brown juvenile feathers emerging at about 20 days of age. By 40 days, the young birds will be sleek brown juvenile falcons.

Over the next few weeks, we'll see a lot of eating, sleeping, and pooping. Poop is a great way to locate the nests and perches of many kinds or birds. See bird poop? Look around for the bird!

5. Will Cain and Abel Syndrome be a problem here?I don't want to say 'No', but I haven't seen it at any of the other Peregrine falcon nests we watch. There is an ample food supply and Michelle and Travis are very good at caring for their young.

6. Mom and Dad are talking to the babies!
Yes, they are! We've already heard Michelle echupping encouragingly to her young immediately before their first feeding. We'll also hear the young food begging (which one website describes as 'screea screea screea'), and kakking: an alarm, defense, and 'annoyance' call. Peregrine falcons are  very vocal. I've had unhappy babies set my ears to ringing more than once.

7. Does the nest smell bad?
It depends! Some falcons are great housekeepers, while others (I'm looking at you, Hibbard plant falcons) let prey remains pile up in the nest. If the nest is messy, the young birds smell interesting to human banders - not bad, but not pleasant: a complex, spicy smell.

---

Things that helped me learn and write about Peregrine falcons:

• Bob Anderson. He knows more about Peregrine falcons than anyone I know. I should see if he'd be willing to echup on video: it is really amazing. Any mistakes in this blog are mine, not his!
• http://www.na.fs.fed.us/spfo/pubs/wildlife/nesting_birds/birds1.htm (nesting birds)
• http://redandthepeanut.blogspot.com/2012/02/notch-in-peregrine-falcons-beak.html (tomial tooth. Very nice photograph and drawing).
• http://falconcam.travelers.com/falcon-faqs.html (falcon facts)
• http://www.pfht.org/LinkClick.aspx?fileticket=nBU15gWur5w%3D&tabid=79 (falcon facts)

Peregrine Falcon FAQ

While we wait for eggs to hatch in Decorah, Valmont, and Fort St. Vrain, I thought I would talk a little bit about Peregrine falcons. Prior to the Decorah Bald eagle cam, Peregrine falcon recovery was what we were known for, to the extent we were known at all.

In Flight
The Peregrine is the fastest animal in the world, diving or stooping at speeds that can reach over 200 miles per hour. Almost everything about it is built for speed, from the baffles in its nose  to the jagged edges of its slim, stiff feathers and long, pointed wings.

The falcon catches other birds in flight by diving on them from above.  As she begins her stoop, she rolls, cups her wings around her body, and tucks in her feet. This change in shape streamlines her profile, yielding an aerodynamic raindrop that can cut through the air at high speeds.

Photo used with permission of Karen Carroll, http://www.birdsofprey.net

As she plummets her nictitating membrane, a transparent 'third eyelid', protects her eyes from dust and debris in the air and a secretory gland helps keep her corneas from drying up. A special cone or baffle in her nose regulates the amount of air entering her nasal cavity, allowing her to breathe and protecting her from damage. A curved flight path keeps her prey in view and reduces her aerodynamic drag. Before she strikes her prey, she'll experience G-Forces estimated at between 25-27 Gs.

The Peregrine meets her prey feet-first. She slows first, unfurling her wings and tail, and dropping her feet. After striking and stunning or killing it outright, she'll loop around in mid-air to retrieve it and take it to a safe place for plucking and eating.  

Falcon Belinda at Xcel Energy's Allen S. King plant aims at a reporter.

Lifestyles of the Fast and Furious
Falcons are roughly crow-sized. Females are about a third larger than males, although they both have bluish to slate grey backs,  barred or streaked white to rusty underparts, and a black hood. Adults have black beaks and yellow feet, although their babies may initially have bluish feet.  This is natural and not a cause for alarm.

Both males and females are highly territorial. Like eagles, Peregrine falcons are relatively monogamous (polygamy has been documented, but isn't common) and may or may not migrate. Unlike eagles, they are relatively solitary birds.

Traditionally, Peregrine falcons nest on cliffs, laying their eggs directly on a scrape they created in a gravel or sandy substrate.  In the midwest, Peregrine falcons generally:

• Lay eggs in late March or early April
• Hatch in late April to early May, or 33 days after the first egg is laid.
• Begin flying in mid-June or later, or about 40 days after hatch.

Peregrines make excellent, attentive parents. The babies cannot thermoregulate (control their temperature) until they are about 10 days old, so Mom spends a great deal of time huddling over them while Dad feeds everyone. As the babies age, both parents spend time hunting. The eyrie is small and the babies, which have among the fastest growth rates in the animal kingdom, are large and hungry. They eat, sleep, poop, and go from white fuzzballs to sleek brown juveniles in about five weeks.

Once they begin flying, the young peregrines spend a lot of learning how to fly and hunt: something that looks a lot like play to most human observers. Their parents will continue to provide some food for their newly fledged young who are not yet self-sufficient.  Come fall, the adults may or may not migrate, but their children will disperse. In our experience, the young falcons tend to leave in September. Once they are gone, they are gone. If they do come back to the nest, their parents will defend it from them. 

What to expect when falcons are expecting
The new Great Spirit Bluff nest cam wonderfully documented falcon courtship. The falcons engaged in  ledge displays on the roof of the nest box, bowing and calling loudly.


As courtship progressed he made a scrape, digging into the gravel with his breast and pushing with his legs to create a depression (males and females will do this - our video shows the male).


Finally, both falcons bowed and e-chupped over the scrape.


The male also courts the female with food. Our video shows him bringing it to the nest box, but falcons also transfer prey midair. There seems to be a little bit of food fight here as well, but think some courtship was going on.


She will probably lay three to four reddish speckled eggs sometime in March. Peregrine falcons do not begin full incubation until after egg number three is laid, so it is normal for her to spend time - even quite a bit of time, depending on how warm it is - away from eggs number one and two. Her eggs should begin hatching 33 days after the third egg is laid.

Mae's eggs, Xcel Energy Allen S. King Plant.
Some egg color variation is normal.

During incubation, she will experience hormonal changes that help keep her incubating. She may appear sleepy or lethargic, and will spend a lot of time picking at gravel and sitting more or less quietly on her eggs. She does most of the incubation, although the male will spell her briefly. The male is smaller and may have a harder time covering all of the eggs, depending how many are laid. We can also expect to see egg rolling (Brent, at the Allen S. King plant, is well-known for this) and some shimmying. This is not a particularly active time for the falcons: I've heard Bob refer to incubation as the 'egg doldrums'.

My reference list:

• Bob  Anderson
• Video makers razzle and chico70
• http://blogs.bu.edu/biolocomotion/2011/12/12/why-can-the-peregrine-falcon-fly-so-fast/
  (peregrine falcon and speed)
• http://blogs.bu.edu/biolocomotion/2011/10/07/the-fastest-animal-on-earth-the-peregrine-falcon/
  (peregrine falcon and speed)
  http://jeb.biologists.org/content/203/24/3755.abstract (curved flight plans and sideways vision)
  http://www.dvrconline.org/raptoradapt.html (raptor adaptations)
  http://www.airspacemag.com/flight-today/falcon.html (Falling with the peregrine falcon)
  http://www2.ucsc.edu/scpbrg/pefabehavior.htm (pefa behavior)

Greetings, I had received a report of a falcons stooping on a Red-tail hawk near Goose Island cliff south of La Crosse, WI. On Saturday I gave a presentation in La Crosse then set off to check out the falcon report. As I drove near the cliff, I could see the cliff owner standing in his yard looking up towards the Goose Island cliff. He has not seen falcons.


I then checked cliffs on the WI side of the river and crossed over at the Lansing, IA bridge. Made my way to down below Dead Cow Bluff and was pleased to see an adult tiercel falcon perched on a dead snag near the cliff mounted nest box. All looks well at this site.

I then drove to the Lansing power plant cliff and hiked to the area directly down below the cliff face. I was pleased to see an adult tiercel falcon perched on the new cliff nest box. We mounted this nest box a few years ago in an attempt to attract the nesting falcons away from their favored ledge where each and every time they have attempted to breed on this ledge the eggs/young were eaten by raccoons. It's looking promising for this pair to be productive since raccoons can't access this nest box.

Things look good for the nesting falcons at the RRP nest box on the Agri-bunge stack house in Mc Gregor, IA.

The cliff nesting pair at Leo's Bluff near Waukon Junction, IA are probably on eggs.

The adult falcons at Larson's Bluff near Lynxville, WI are looking like they will use the main cliff this year. With the nesting falcons at the Dairyland Power Genoa plant and the other nest sites mentioned above, we have six pairs of nesting falcons in a relatively small area of the Mississippi River.

John and I will be checking all of the cliffs near Petosi, WI and Balltown, IA in a helicopter this next week. We will also check for occupancy at the cliffs in pool 13 upstream of Clinton, IA. All of these cliffs do not have roads nearby and to survey by boat would take days. Look for a report of cliff assessment and GPS coordinates later this next week.

Mississippi River Peregrine Falcons: Great News for Cliff Nesting Falcons

Tuesdays must be the lucky day to find falcons on the river cliffs. On 4/8/08 we located two adult falcons defending Pepin Heights cliff just south of Lake City, MN. On 4/15/08, I spent the entire day surveying river cliffs and was most pleased to find two adult falcons defending a small cliff just north of the town of Minneiska, MN.

It appears that falcons are now taking to smaller or secondary cliffs. However, the one constant is that all cliffs with falcons tower directly over open water. Will this change when all cliffs directly facing water are occupied?

The following is a list of cliff sites with falcons on territory.

1. West Bluff near Maiden Rock, WI: Historic eyrie with falcons back for the third time.
2. Maiden Rock: The matriarch of river cliffs. Purchased and managed by the West Wisconsin Land Trust.
3. Maassen’s Bluff: Four miles north of Alma, WI.
4. 12 Mile Bluff: On the south end of the town of Alma, WI.
5. Castle Rock: Across the river from Winona, MN.
6. Lynxville, WI cliffs: The falcons are back on Larson’s Bluff.
7. Lock and Dam 9: This is the third year for this small cliff to attract falcons. It’s interesting to note that in 2006 there was an adult male paired with an immature female. 2007 an adult male paired with an immature female. 2008 adult female, immature male.
8. Fountain City: Two adults taking to the nest box mounted to the cliff in 2006.
9. John Latsch: Adult falcons present. Bandings carried out by Raptor Center.
10. Queen’s Bluff: South of Winona, MN Bandings carried out by Raptor Center.
11. Homer cliff near Homer, MN: Two adult falcons defending
12. Great Spirit Bluff: South of Dresbach, MN.
13. Leo’s Bluff, Waukon Jnct, IA: The two adult falcons at this cliff have moved to a new cliff just upstream from Leo’s Bluff. This is the third time the falcons have moved upstream. Dan Berger jokes that this is the result of global warming.
14. Pepin Heights 1: We confirmed falcons on this cliff on 4/8/08. On 4/15/08 I saw them carry out a food transfer. The winds were too strong to attempt to read bands on the top of the cliff. I even got a creepy feeling while standing on the top of this bluff being buffeted by 30+ winds.
15. Hussen’s Bluff near Minneiska, MN: I confirmed two adult falcons on this small cliff yesterday morning. I met with the land owner who is excited about his falcons.

Cliffs that have had some falcon activity

1. Twin Bluffs: Near Nelson, WI. Two falcons were present on early visits to the cliff but on 4/8/08 no falcons were observed. This same day, two falcons were observed at the Wabasha Bridge. The owners of this cliff have asked us to install a nest box on the cliff wall.
2. Trempealeau, WI: Falcons were observed several times in 2007. We have not seen falcon activity as of this writing in 2008.
3. Brownsville, MN: There are two cliffs south of Brownville that have in past years attracted single falcons.
4. Alma Marina cliff: This is a historic cliff nest site for the peregrine falcons. Dan Berger working with Fred and Fran Hamerstrom trapped an adult female falcon below this cliff in the early 50’s. We’ve seen falcons at this cliff several times over the years however, last year and, this year, Great Horned Owls are nesting in the one prominent eyrie.
5. Goose Island cliff: We have had falcons visit this cliff off and on over the last few years. The land owner who lives near the base of this cliff will let us know if falcons are seen once again.
6. Hastings cliff: Falcons have nested in the nest box mounted to the small cliff and also on a nearby bridge. I have not heard what site the Hasting falcons are using this season.

Bob Anderson
Director, Raptor Resource Project