Friday, March 31, 2017

Why a functioning EPA is important for birds

The EPA, or Environmental Protection Agency, is a US government agency established in 1972 to protect human health and the environment. By the early 1970's, Americans were increasingly aware of the dangers posed by pollution, the indiscriminate dumping of sewage and industrial chemicals, and the widespread and unregulated use of pesticides, herbicides, and toxic agents. Peregrine falcons, bald eagles, and other birds were critically endangered and at risk of extinction, the Cuyahoga river had famously caught fire several times, Great Lake Erie had been declared dead, and smog regularly blanketed America's largest cities. People were organizing at local, state, and national levels to get ordinances and laws passed to reduce pollution and penalize polluters. In some cases, people were driven by concerns about the future, but in many others - like Los Angeles - they were concerned with immediately improving health and saving lives.

Prior to the Clean Air Act, the Clean Water Act, and the EPA, there were no legal or regulatory federal mechanisms to protect the environment. While communities could address local problems, water and air don't have a fixed address. A regulatory mechanism was needed that would allow enforcement across county and state lines, address pollution on land and waterways owned by the federal government, and provide funds for cleaning up large, extremely toxic messes like this one, which is still affecting the Channel Islands. Following the introduction and passage of several bills related to environmental concerns, President Nixon proposed a new agency on July 9, 1970, to consolidate the environmental responsibilities of the federal government. Congress approved the proposal and President Nixon signed an executive order establishing the EPA on December 2, 1970.

Why does this matter to human health and wildlife?  Take a look at the EPA A-Z index: The EPA is able to regulate and enforce environmental and human health laws as related to air (the Clean Air Act and Amendments), water (the Safe Drinking Water Act, the Clean Water Act, the Water Quality Act, and the Safe Drinking Water Amendments), land (the Wilderness Acts, the Wild and Scenic Rivers Act, and the Surface Mining Control and Reclamation Act), endangered species (the Marine Mammal Protection Act, the Endangered Species Act, and the Endangered Species Preservation Act), Hazardous Waste (the Solid Waste Disposal Act, the Resource Recovery Act, and the Hazardous and Solid Wastes Amendments Act) and human health (the Federal Environmental Pesticide Control Act, the Toxic Substances Control Act, the Nuclear Waste Repository Act, and the Food Quality Protection Act). In short, the EPA played a very important role in the cleaner air, the cleaner water, and the formerly endangered species we so enjoy today.

Perhaps most important to bald eagles, peregrine falcons, brown pelicans, and many other birds, the EPA banned DDT in the United States in 1972 based on its adverse environmental effects. But that isn't the only banned chemical that affects birds. Remember DN2's death last year? He was poisoned by methomyl, a member of the carbomate chemical family. Carbofuran, a related chemical, killed millions of birds each year before the EPA canceled it for use on crops in 2009. In 1990, diazinon was classified as a restricted ingredient and banned for use on golf courses and turf farms, marking the first time regulatory action was taken specifically on behalf of birds. It was banned entirely on January 1st of 2005. Chlordane was banned for home, garden and agricultural uses in 1983. It is persistent in the environment and still poisons birds today, but not at the levels it once did. Monocrotophos was removed from use in the United States in 1991, although it was linked to huge die-offs of Swainson's Hawks on their wintering grounds in Argentina. You can read more about the American Bird Conservancy's successful intervention here.

So in short, a working EPA is important for birds because its actions have directly benefited many birds including eagles and peregrine falcons, and its enforcement of environmental laws has resulted in cleaner air, cleaner water, and better health. Concerned only with the economy? The estimated economic benefit for banning lead ranges from $110 billion to $319 billion for each year's newborns. The yearly economic benefit of that alone is far bigger than the EPA's annual budget.

So what can we do? In the short term, you have until May 15, 2017 to comment on Executive Order 13777, issued on 2/24/17, which directs agencies to establish a Regulatory Reform Task Force to make recommendations about potential repeal, replacement, or modification of EPA regulations. We know it sounds boring and unimportant. We know that a lot of people who follow the eagles have busy lives. We know that our fans come from all over the political spectrum. But conservation isn't red or blue, it is important to birds and humans, and we are asking people to take the time to read through the materials and comment.

Why?  We asked you to comment on the 30-year take of bald eagles, and you did. Did the 30-year take pass? Yes. But while it would have been good to see it voided, your comments resulted in a better ruling overall, with more safeguards put into place and outside auditing of companies that choose to participate in the 30-year take program. Without your comments, it would have been a lot worse.

If you would like to read more about the EPA and birds before commenting, follow these links:

In the long term, you can educate yourself and others about the substances most toxic to birds. You can support organizations that advocate and do research on behalf of birds. Of course I like it when people support the Raptor Resource Project, but you should also take a look at the American Bird Conservancy and the work they do. You can get involved in local projects: remember, our national concern for the environment grew in part out of local issues, whether it was choking smog, the loss of soil, the contamination of water, or the need for local parks and wild land. We can all keep reminding our congressional representatives and senators that conservation and the environment are important to us. And we should all take strength, determination, and resolve from our polluted past: strength, since we have made significant improvements; determination, so we can keep moving forward; and resolve that we won't go back to those days again.

Things that helped me learn and write about this topic:
Keep in mind - we've come a long way, baby!

Eaglet Growth and Development: Week One

We are watching eaglets at three nests right now: Decorah, Decorah North, and Xcel Energy Fort St. Vrain. The oldest (FSV34) is five days old, and we're still waiting for DN6 and all of the Decorah eaglets as I write this. What can we expect in the first week of watching? Weight Gain!

DN4 at the Decorah North Nest
Like humans and other animals, growing nestlings have developmental milestones. The eaglets spend roughly the first week of their life gaining weight. They aren't able to thermoregulate yet, so depending on the weather and temperature, they may spend a lot of time under Mom and Dad. We'll see them eat, sleep, scuffle, and grow stronger as they interact with one another.  They will go from roughly 3.2 ounces - about the weight of 18 nickels - to roughly 16 ounces or one pound, increasing their weight five times over in just seven days.

Weight gain (g/day) as a function of age for male and female nestling Bald Eagles
This chart was reprinted from The Wilson Bulletin 96: 527 from an article published by G. R. Bartolotti (1984) with the written permission of the Wilson Ornithological Society. 
Many structural features, including foot pads, tarsi, and hallux claws, won't start rapid growth until 10-15 days after hatch. But the hatchlings' mid-toes and culmen - the dorsal ridge of the upper mandible - are already growing longer! Food is the root of all else besides, so it isn't surprising that the culmen achieves maximum growth in the first ten days. I suspect that the mid-toe aids balance, a crucial element of sitting up and exploring the nest. While our eaglets won't truly stand on their feet until they are roughly four weeks old, they will begin to shuffle around the nest on their tarsi long before that.

Enjoy the downy bobbleheads this week! By next week, they will already be growing their longer 'wooly' second or thermal down and alternately worrying and thrilling us with their interactions and sojourns around N2B.

The general stages of eagle development are:

  • Stage 1 - Structural growth. In their first thirty-five to forty days of life, eagles grow very rapidly, gaining weight and building bones, muscles, tissue, and features like tarsi, footpads, toes, and claws. This phase of development slows down about halfway through an eaglet's time in the nest, even though individual features might continue some level of growth.
  • Stage 2 - Feather and flight-related growth. Eagles grow four sets of feathers - natal down inside the egg, thermal down, juvenile feathers, and adult feathers. While thermal down starts growing at about ten days and juvenile flight feathers at about 27 days, feather growth doesn't overtake structural growth until thirty-five to forty days after hatch. Flight muscles also begin growing as eaglets wingercize, flap, hover, and eventually branch and fledge.
  • Stage 3 - Neurological Coordination. Eagle watchers know how ungainly eaglets can seem! As they grow, they become more adept at controlling beaks, legs, wings, and feet. They learn to stand on their own feet, tear food, self-feed, and flap their wings, going from cute but clumsy clown clompers to graceful young eaglets poised at the edge of fledge.

I'm not sure how familiar many of you are with the cortical homunculus, an image-based tool that maps tactility. We discussed it very briefly in this blog and I'll include links below. While useful and extremely cool, most cortical homunculii are static - that is, they reflect just one phase (usually adult) of an organism's life. But an eaglet's cortical homunculus will differ from an adult's as body parts and associated skills are gained and neural pathways developed. Our eaglets' brains and bodies are rapidly growing and changing as they gain the skills they need for life outside the egg!

Things that helped me write this blog, with a few considerations:

Thursday, March 23, 2017

What's inside those bald eagle eggs?

It is 31 days since egg number one was laid in Decorah, 32 days since egg number one was laid at Decorah North, and 36 days since egg number one was laid in Fort St. Vrain. We are starting hatch watch for Fort St. Vrain on Saturday, Decorah North on Sunday, and Decorah on Monday. The embryonic eagles are either in or approaching their final stages of development now, but what did they look like as they developed and grew inside their eggs?

Dr. Peter Sharpe from the Institute for Wildlife Studies developed a table of bald eagle embryonic development based on work done by Hamburger and Hamilton (1951). While not all bald eagle eggs hatch in 35 days, the stages of development look something like this...

Development of a chick, drawing from Frank Lillie photos. Artist William Sillin
From 0 to 4 days: A single cell is formed by the union of sperm and egg. It divides into multiple cells and forms layers. Head and tail are established, the emerging embryo divides into blocks called somites, and basic life support structures begin to develop, including the nervous system, skin, circulatory system, gastrointestinal system, and optical system.  The embryo turns onto its left side. Its heart begins to beat roughly 72 hours after incubation begins.
Chicken embryo at roughly two days incubation: equivalent to an eagle at about 3.5 days
At four days of age, the embryonic eagle doesn't look anything like a bird, but it has inside and outside layers, it can transport materials through its developing circulatory system, and its nervous system has an anterior-to-posterior template in place. The brain and nervous system will continue to grow and change, but the stage is set for the development of a skeletal system, limbs, a beak and tongue, foot and wing digits, and organs. 

From 3.5 to 9 days: The amnion closes, sealing the developing embryo inside the egg's innermost membrane. The allantois forms to sequester liquid waste and exchange gases through the porous eggshell. Wings, tail, and leg buds form. Eyes develop pigment.  Leg buds grow larger than wing buds and limbs begin to form. Elbow and knee joints are distinct by roughly 8 days and digital grooves - the precursors of toes and wing structures - are distinct by roughly nine days. The embryo's beak and tongue begin to form.
Chicken embryos roughly 23 to 25% of the way to hatch
At nine days, the minute embryonic eagle is about 25% of the way to hatch and still doesn't look especially birdlike. It has a head, eye pigmentation, stiff differentiated limbs, the beginnings of a beak, rudimentary digestive organs, and a defined sex. The stage is set for further organization as the embryo develops an egg tooth, true eyes, and feather germs. 

From 11 to 17 days: The egg tooth and two scleral papillae form on the 11th-12th day. Limbs are bent. Dorsal feather germs form on the 12th day. A nictitating membrane is visible on day 13. Ventral feather germs develop, the eyelids begin closing, and flight feather germs develop. 

A chicken embryo roughly 50% of the way to hatch
At 17.5 days, we are roughly halfway to hatch. Our embryo's head is disproportionately large, but it is definitely a bird. It has a beak, distinct toes, bent limbs, and eyes that take up most of its head. Its eyes and eye cavities aren't done forming and it needs to develop scales, nails, rough pads and spicules, and down feathers. Its yolk sac and small intestines are still outside its body cavity, and it has a lot of growing to do!

From 18 to 23 days: Leg scales, tiny talons, and plantar food pads appear. The eyelids are almost closed and the eyes are no longer quite as large in proportion to the rest of the head.

We are 65% of the way to hatch! Other than the closing of the body cavity, most major morphological changes are done. The eyelids will close, the eyes will grow into their sockets, the eaglet will develop natal down, it will internalize its egg yolk sac, its body cavity will close (leaving behind an egg yolk sac scar) and it will position itself for hatching! 

So what happens right before hatch? Just a few days from external pip, the rapidly growing embryo is taking up nearly all the space in the egg. It...
  • Turns so that its head is at the large end of the egg next to the air space.
  • Pierces the internal membrane - the internal pip - and begins to breathe air with its lungs. Hatch has started!
  • Takes the yolk sac into its body as it consumes most of the remaining albumen and yolk. 
  • Grows enough to contract the hatching muscle, pointing its head up and positioning its egg tooth against the shell of the egg. The eggshell is thinner and weaker than when it was laid, since the growing embryo absorbed calcium from the shell for its bones. 
  • Rubs its egg tooth against the shell, which cuts a small hole. We have an external pip!
  • Rotates its body, slowly cutting a ring around the shell.
  • Pushes its body against the shell, forcing the shell apart.
  • Works itself free of the shell membranes and halves. The eaglet has landed and hatch is complete!
We are looking forward to hatch later this week! Curious about what's in store? Watch this 2015 video of the very final stages of hatch in N2. 

Illustrations were taken from Popular Science Monthly/Volume 71/September 1907/The Problem of Age, Growth and Death III:  Link. Thanks to artist William Sillin for allowing us to use his lovely illustrations: (check it out - his illustrations are very cool!). Also take a look at this cool plate by Keibel and these lovely photos of chicken embryos:

Things that helped me learn about this subject:

Tuesday, March 21, 2017

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
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!

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

Monday, March 20, 2017

Message from the Director

It has been a busy start to the year, but it has been productive and very enjoyable.  A warm welcome to our teachers and classrooms that are following along!  We have been working hard to get raptor cams ready for nesting season, training volunteers to operate them, and telling the interesting stories as we watch nature unfold and enter a new cycle of life.  If you are an educator and would like a classroom account, please visit

Two stories come to mind….the first one as each day starts is how to best share the raw beauty that comes with viewing our Decorah Eagles and other raptors as they do what comes naturally.  We are drawn to that connection with the natural world they represent.  Who could imagine that we would recently watch and wonder about the first vivid footage we have seen of Mom North vocalizing while sleeping and dreaming [video:]!  I also had to hunt down the video footage captured by our videographers when I heard about the confrontation between the first female peregrine falcon to arrive at Great Spirit Bluff with our resident female Michelle as she returned a week later to claim her nest and mate. It was not too rough, but I can honestly say I was rooting for Michelle and had to laugh as some of you joked about Newman having some explaining to do! [video:]

The second story is what a difference we can make by leading as an example and using our energy and talents to advocate for the raptors and nature around us.  Most of us have been touched by the example set by Bob Anderson and his RRP partners in raptor conservation and research.  It has been a time of reflection to watch the recent Iowa Public Television movie (The Eagles of Decorah) about the discovery of the Decorah Eagles and subsequent production of the movie “American Eagle”.  It is that passion that has brought us all together to carry on.

Our second annual fundraiser at the Celtic Junction in St. Paul was an event to remember and served as a kick-start to the year.  It was a donation of time and musical talent, one of the many you share, showcasing contributions that help us fulfill our mission.  This year we are focusing some of those efforts on kestrels, osprey, and telling stories of the unique Driftless Area.  I can’t wait to share our first newsletter with you all soon!  We now prepare to monitor peregrine falcons as they return to their historic bluff eyries.

There are exciting times ahead watching and experiencing Nature’s reality TV and sharing our love for the raptors who are only part of the bigger picture.  Spring is just around the corner and we have some exciting projects to share that are in process….stay tuned and need I remind us all to get outside and capture the outdoor experience! It won't be long until eggs start hatching!

John Howe
Director, Raptor Resource Project

Thursday, March 09, 2017

Sweet Eagle Dreams

Do bald eagles dream? Some footage of Mom North had us discussing the question today. In the video, Mom North appears deeply asleep, with her head tucked underneath her wing. At eleven seconds, she starts to stir. Still tucked in, she starts to vocalize. She stops, stirring very briefly at 50 seconds before settling back down. The behavior appears remarkably similar to the dreamy stirrings of slumbering dogs, who quiver, twitch, ‘run’, and even growl in their sleep.

A study on sleeping finches found that their sleep is quite complex. The slumbering finches experienced slow wave sleep (SWS), rapid eye movement sleep (REM), intermediate sleep (IS), and K-complex sleep, which aids memory consolidation in human beings.  REM episodes were brief early in the night but became longer as REM density increased and intervals between REM sleep decreased. Unihemispheric sleep (sleep with one eye open) was less common, of a shorter duration, and almost exclusively restricted to the light phase of sleep: think napping over deep sleep (“I’m not sleeping, I’m just resting my eyes!”).

Why is complex sleep important? Bird brains don’t look a whole lot like our brains. Given the lack of structures like a neocortex, human researchers have tended to assume that birds aren’t capable of complex neurological activity, including dreaming. But studies like this show that birds are much more complicated and intelligent than we think. The ethology of crows (and some other birds) has proven that birds have a sense of past and future, which allows them to plan, change and weigh consequences, and refrain from unproductive actions. Some of this stored information is replayed while sleeping, which may help birds develop memories, practice daily activities, or process events. So what were the zebra finches dreaming about? The same study found that the sleeping finches replayed, rehearsed, and perhaps improvised songs in their sleep. In short, songbirds – at least these songbirds – dreamed of singing.

Do eagles experience complex sleep? We don't know, although the authors of the zebra finch study state that there could exist a greater complexity to sleep structure across bird species than has commonly been recognized.  Eagles experience many of the behaviors we see in birds like crows, which are renowned for their intelligence: language, delinquency, insight, emotion, frolic, passion, wrath, risk taking and awareness. Eagles organize in social multi-age groups away from their territories, follow consistent migration paths between winter and summer grounds, select and retain mates, build large, complex nests, incubate and brood young in challenging conditions, teach their young, learn from life events, and recognize and remember things on their territories. They clearly have intellect, even if it isn’t organized much like our intellect, and they most likely experience complex sleep. Perhaps our question should be not "Do eagles dream?" but rather, "What do eagles dream about?".

We reached out to Marge Gibson from the Raptor Education Group, who responded that her birds (a macaw, doves, and a turkey) dream and vocalize while dreaming. Several forums on pet birds, especially Psittaciformes, discuss dreaming in birds, although I wasn't able to find many videos of the behavior. 

Things that helped me learn about sleep in birds:

Bonus fun!
This blog addressed primarily avian dreaming, but avian sleep is an interesting topic and we'll return to it in another blog!