Celebrating the Centennial! 100 years of Bird Conservation

On this date in 1916, the first Migratory Bird Act was signed between the United States
and Canada, serving as the catalyst for a century of bird conservation actions. At the turn of the twentieth century, bird populations were in peril as a result of unregulated shooting for the food and fashion industries. Recognizing the need for collaboration to protect species that traverse their borders, partners in the United States and Canada drafted an agreement to cooperatively manage and protect birds that migrate internationally. The act was the first international agreement forged to protect wild birds, and among the first to protect any wildlife species.

Mom and Dad Decorah don't migrate, but many of the birds we watch do! D1 went to Canada for the summer, while many of Eagle Valley's eagles visit the United States for the winter. North American peregrine falcons have been reported on oil rigs in the Gulf Coast (Candace W/Z, a bird that Bob banded), Chile (the incredible Island Girl), and Costa Rica (the lovely Inmaculada), just to name a few. As Scott Weidensaul says: "At whatever moment you read these words, day or night, there are birds aloft in the skies of the Western Hemisphere, migrating. If it is spring or fall, the great pivot points of the year, then the continents are swarming with billions of traveling birds..."

It is August 15th. Grasshoppers are leaping, goldenrod is blooming, indigo buntings are visiting my feeders, and some of the birds that summer in Minnesota and parts north will begin migrating soon. A great tide of birds will wash down from the north, moving down the Mississippi river towards the southern US, the Caribbean, Mexico, and Central and South America. They will fly over cities, counties, states, provinces, precincts, districts, and nations - a patchwork of histories, languages, cultures, religions, economies, shared experiences, and beliefs - with no passport or knowledge of boundaries other than those imposed by landscape and weather. What has that tiny indigo bunting at my feeder seen? How many miles have passed beneath its wings? What is it like to be an artic tern, which flies about 44,000 miles per year and experiences nearly perpetual daylight as it travels from Greenland to Antarctica and back again? What pulled D1 north 920 miles to Hudson's Bay every summer and what did it feel like when the fishhook of dispersal started tugging her away from the only world she had ever known?

There are a lot of reasons that birds are important. They connect people with nature, which gives us a reason to preserve the landscapes they need. They contribute important environmental benefits, including insect and rodent control, pollination, and seed dispersal. They are an important part of our economy, generating about $500 million annually in direct hunting revenue in my home state of Minnesota alone - and that doesn't count the money spent by birds, bird banders, and people who attend birding festivals. But to me, the most fascinating part of birds will always be their mystery. I am grateful for the window into their world that technology has given us, and for treaties like the Migratory Bird Act to help protect them as they wing their way through our world.

A brief history of three Acts that protect Bald Eagles
The ornamental plume trade provided the catalyst for two of the three Acts that protect bald eagles. In the late 1800s and early 1900s, hats decorated with plumes and other bird parts were a must-have for fashionable ladies. How bad was the plume trade? In February 1886, a young New York ornithologist named Frank Chapman set out on expedition to uptown Manhattan, counting the number of ladies' hats adorned with feathers and other bird parts. Over the course of two trips, Chapman counted 542 hats adorned with 174 whole birds or their disembodied parts. In Chapman’s assessment forty different bird species were represented in his count. As Lapham's Quarterly pointed out, this made uptown Manhattan one of the most diverse bird-watching territories in the world. It is estimated that over 5,000,000 birds were being killed annually to decorate hats and clothing.

Hats decorated with ornamental plumes were a must-have for fashionable ladies! 

Woman wearing a "Chanticleer" hat  made of bird feathers, circa 1912.	Opera singer Emmy Destinn  wearing a plume-covered hat, around 1909.

The Lacey Act and the Migratory Bird Treaty Act were passed largely to regulate and combat the ornamental plume trade, which decimated bird populations and drove a number of species to extinction. The Lacey Act, passed in 1900, was the first federal law protecting wildlife. It prohibited market hunters from selling poached game across state lines and was designed in part to stop the flow of feathers from the American countryside to the great millinery centers of New York and London. Iowa fans can be especially proud, since the Act was introduced by Iowa Congressman John Lacey.

The Migratory Bird Act was a landmark agreement signed by the United States and Great Britain in 1916 with the goal of 'preserving those species considered beneficial or harmless to man'. Like the Lacey Act, it provided a tool to limit the extensive ornamental feather trade and the unregulated shooting of birds. Both the US and Great Britain (acting on behalf of Canada, which was part of the British Empire) realized that international treaties were necessary to protect animals with no international boundaries. The two countries agreed to stop all hunting of insectivorous birds and to establish specific hunting seasons for game birds.

The Migratory Bird Act agreement was implemented two years later with the passage of the Migratory Bird Treaty Act of 1918. The act established penalties for people who broke the law, making it a crime to pursue, hunt, take, capture, kill, or sell a migratory bird or any of its parts, including nests, eggs, and feathers. This effectively shut down the ornamental feather trade and gave species like the snowy egret a change to rebound.

Breeding plumage: Far better on the snowy egret!
By Len Blumin from Mill Valley, California, United States (Snowy Egret display) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

While bald eagles were covered under the Migratory Bird Treaty Act, they hadn't been directly affected by plume hunting. But sport shooting, bounty hunting, and habitat loss were another matter. The Bald Eagle Protection Act was enacted by Congress in 1940 to protect the bald eagle from direct hunting and habitat encroachment. As the territory of Alaska demonstrates, we haven't always admired bald eagles. Between 1917 and 1952, 128,273 bald eagles were killed and submitted to the Alaska Territorial Treasurer for bounty. We have no figures for the amount that were simply killed offhand or to provide feathers and parts for the trade in "authentic" Native American artifacts, but Congress felt that an act was needed to protect the bald eagle from extinction. The Golden eagle was added in 1962, amending the law to the Bald and Golden Eagle Protection Act.

While there are many complicated issues around the Migratory Bird Treaty Act (consider the controversial proposed bald and golden eagle take proposed by the Fish and Wildlife Service) it has saved millions if not billions of birds since the initial treaty was signed in 1916. Let's celebrate the act and keep moving forward to save birds for the next 100 years! Migratory birds need our help: as Steve Holmer, Senior Policy Advisor for the American Bird Conservancy, pointed out: "Forty percent of all migratory bird species are in decline, so it is urgent that we put in place practices we already know will save birds from needless deaths.”

Links

• American Bird Conservancy's Blog on the MBA: http://bit.ly/2b9zzUY. Go there, read the article, and use their tool to contact your lawmakers about preserving the act! 
• Migratory Bird Centennial Page: https://www.fws.gov/birds/MBTreaty100/index.php
• Migratory Bird Treat Centennial Pledge (note: there is a little friendly competition going on between the US and Canada, so fans from both countries should consider downloading the pledge!): https://www.fws.gov/birds/mbtreaty100/pledge.php
• Interactive Bird Conservation Timeline: Because who doesn't love timelines? https://www.fws.gov/birds/MBTreaty100/timeline.php
• Audubon - The Evolution of the Migratory Bird Treaty Act:
  http://www.audubon.org/news/the-evolution-migratory-bird-treaty-act
• The Audubon Society was founded by Boston socialites Harriet Lawrence Hemenway and Minna B. Hall, who were horrified by the toll that their lovely hats took on birds. You can learn more about them here: http://wbaa.org/post/hats-women-who-saved-birds and here: http://www.laphamsquarterly.org/roundtable/fine-feathered-friends.

The Fish and Wildlife Service has a long list of important conservation messages. I chose my favorite ones to post here! Remember, times change, and threats change with them.

What is the main threat to migratory birds? 

• Habitat loss due to urban development, agriculture and other human activities is the main threat to migrating birds. [Note: 'other human activities' is probably referring to global climate change].
• Migratory birds depend on suitable breeding and wintering grounds and stopover sites where they can rest and feed along their migratory routes. The loss of any sites used by the birds during their annual life cycle could have a dramatic impact on their chances of survival.

What can we do about it? 

• Conserve habitat - conservation works! Where we have invested in healthy habitats, birds are doing well. Healthy birds mean healthy forests, wetlands, grasslands, shorelines and oceans [and healthy forests, wetlands, grasslands, shorelines, and oceans mean healthy birds].
• By conserving birds we conserve our American landscapes and the economies and ways of life that depend on them. From farmers and ranchers to outdoor recreationists to children, we all benefit when birds thrive.

#birdyear #thenext100years

Eagle tracking: can you do something about the tracking antenna?

We were asked a lot of questions about eagle tracking during After the Fledge. D1, D14, Four, and D24 and D25 are part of a study by biologist Brett Mandernack from Eagle Valley: the first and, to date, most extensive tracking study in of free-living eagles in the Upper Midwest. Brett’s transmitter and field research have collected a wealth of data about the migratory, wintering, and summering behavior of bald eagles.

The most commonly asked question involved the PTT antennae located on the eagles’ backs. Could they be removed or shortened? How do the transmitters work and why are they the length they are? This blog attempts to answer those questions. Warning: it requires a fair amount of reading and has a long resource list at the end!

Can you get rid of the antenna?
We cannot. An antenna is needed to transmit data from the PTTs worn by our eagles. The PTT and GPS units from Geo-Trak Inc. collect and encode data about location, heading, speed, time, activity, and transmitter and battery performance. The encoded data is supplied as energy to the antenna, which radiates it as UHF radio waves to the Argos satellite network orbiting 528 miles (850 kilometers) over our heads. From there, ground stations receive real time data from the satellites and retransmit it to regional processing centers where we can access it. No antenna = no data.

Why can’t the antenna be smaller? Couldn’t it be part of their leg bands?
Let’s start with a quick primer. When we talk about radio waves, we are really talking about a small part of the electromagnetic spectrum - the range of all types of electromagnetic radiation (EMR). EMR is classified by wavelength into radio wave, microwave, terahertz (or sub-millimeter) radiation, infrared, the visible region that we perceive as light, ultraviolet, X-rays and gamma rays.

Our transmitters are talking from eagles on the ground to satellites in space using radio waves with a frequency of 401.664 MHz.  As the chart above shows, the higher the frequency, the shorter the wavelength. The shorter the wavelength, the smaller the antenna. So if a higher frequency means a smaller antenna, why aren’t we broadcasting at, say, 30GHz – the top end of the radio spectrum? An organization called the International Telecommunication Union coordinates the shared global use of the radio spectrum, which includes assigning radio frequency allocations for space communication. 399.9 - 403 MHz is the band that ITU has allocated for navigation, positioning, time and frequency standard, mobile communication, and meteorological satellites. Geo-Trak’s satellite tracking products use the Argos satellite network, which transmits and receives data at 401.650 MHz (± 30 kHz). Argos is using the highest frequency available to them.

So why does frequency impact antenna size? The wavelength of a frequency is the distance an electromagnetic wave travels to complete one cycle. As the image at right shows, a 401.664 MegaHertz signal (a signal that oscillates, or moves through a complete cycle 401.664 million times in one second) has a full wave length of 29.38 inches, a half wave length of 14.69 inches, and a quarter wave of 7.34 inches.

For the antenna to radiate properly, it needs to match either the full wave or one of its major harmonics. Therefore, 7.34 inches – a quarter wave - is as short as the antenna can be and still function. Perhaps improvements in materials, circuitry, and/or manufacturing will someday allow smaller antennae to be used in satellite tracking, but for now, a whip antenna is our only choice for robust ground to space communication.

The image at left shows an electrical wave oscillating through a full wave antenna, where the antenna is the same size as the wavelength. If the antenna were longer or shorter than the wavelength it is propagating, it would work less efficiently or not at all. A dipole antenna breaks the wave into two pieces, so it can be half as long as a full wave antenna. A quarter wave antenna - the kind used on our PTTs - breaks the wave into four pieces and can be a quarter the length.

I found the distance traveled to be quite fascinating. If you do the math, 29.38 inches (the distance it takes for our signal to complete one cycle) multiplied by 401,664,000 cycles per second equals roughly 186,000 miles per second. It takes a lot less than a second for messages to travel from the Dynamic Duo (D24 and D25) to the Argos satellite system 528 miles overhead.

Will electromagnetic radiation of an antenna hurt the eagles?
No. Terms like electromagnetic radiation are frightening, but not all electromagnetic radiation is harmful. Innately dangerous electromagnetic radiation is found in the high-frequency end of the spectrum, since high frequency waves are a lot more energetic than low frequency waves.  Think of it this way:  gamma rays have frequencies of 1 x 10²¹ Hertz, which means that the wavelength crests, or hits its highest potential energy point, 1 sextillion times or cycles per second. That packs a punch! By contrast, visible light has a frequency of around 5 x 10¹⁴ (500 trillion cycles per second), microwaves have a frequency of 1 x 10¹⁰ Hertz (ten billion cycles per second), and our radio waves have a frequency of 4 x 10⁶ (400 million cycles per second).

Power is also a factor. I have a 1500-watt microwave oven that can damage living tissue. However, it is literally almost 7000 times more powerful than the 225mW solar units that power the transmitter. Even cellphones produce radio waves that are more powerful and energetic than ours.

What about insect studies? Those antennae are really small!
A lot of really cool work is being done with insects. While some of the technologies involve active transmitters, which require batteries, others use passive devices like RFID tags and geolocators. Passive devices don’t require much power and can be made extremely small. A couple of links:

• How microtransmitters help solve nature’s riddles: http://www.popularmechanics.com/science/animals/a5005/4342060/
• Scientists put backbacks on dragonflies to track their brains in flight: http://www.wired.com/2013/06/dragonfly-backpack-neuron/

Unfortunately, passive devices can’t transmit. Researchers don’t get data unless the animals move in close proximity to a reader (think of a feeding station where animals might gather), or they are recaptured for a data download. Geolocators could be used to track migratory peregrine falcons that return to the same nest box year after year, but they aren’t a good fit for tracking juvenile or sub-adult eagles that wander unpredictably and often widely.

The tiny little transmitters used in tracking insects are very cool – check out that tiny backpack! – but they have short battery lives (7-21 days) and a limited tracking range on the ground only (100-500m). As neat as they are, they aren’t suitable for tracking juvenile and sub-adult eagles either.

In short…
We can’t get rid of the antenna, which is as short as it can be given the frequency of our ground to space transmission. Argos did a great job designing a package that is light, safe, reliable, and trackable almost anywhere on earth, especially given the physical requirements of the transmission system. The transmitters do not harm bald eagles or impact their social or reproductive interactions with eagles that aren’t wearing transmitters. Passive devices aren’t a good option since juvenile and sub-adult eagles range unpredictably and often widely before settling down to nest, while tiny active devices have short battery lives and a limited ground-only tracking range – something that won’t work for animals that can fly hundreds of miles and live relatively long lives.

However, research into insects and small birds is driving tracking devices to become even smaller.  If at some point appropriate tracking hardware becomes available with a smaller antenna, we will use it.

Did you know?
The wavelength and frequency of electromagnetic waves are closely related. If you have a frequency, you can get the wavelength, and if you have a wavelength, you can get a frequency. With the wavelength, you can determine the length of the antenna you need to transmit or receive radio waves at a given frequency. The formula looks like this:  Wavelength = Wave speed/Frequency.

Let's say that I have a frequency of 401.664 MHz, or 401,664,000 cycles per second. The wave speed is the speed of light, which can be expressed as 3x108 m/s or 300,000,000. If I divide 300,000,000 by 401,664,000, I get .7468 meters. Since I was raised in the English system, I immediately convert it to inches or feet, which gives me an antenna length of 29.38 inches. This was very helpful when trying to determine why the antennae on our PPT systems are the length they were. This web calculator provides lengths for half and quarter wave antennas if you want to play around with making them: http://www.csgnetwork.com/antennagenericfreqlencalc.html

What could you do with an antenna? There is a community of people that listen to the earth via homemade VLF radios. This website provides an introduction to the concept and some online streams: http://abelian.org/vlf/

Resources that helped me learn and write about this:

• Argos: http://www.argos-system.org/?nocache=0.5821460292957814
• Northstar Telemetry: https://www.northstarst.com/
• GeoTrak Inc: http://geotrakinc.com/
• Radio frequencies for space communication: http://www.spaceacademy.net.au/spacelink/radiospace.htm
• NASA’s outreach directive website, especially http://go.nasa.gov/2blS3RQ and http://go.nasa.gov/2bocjWm and http://go.nasa.gov/1Augpvq
• Understanding antenna specifications and operations: http://bit.ly/1Ool1vK
• Whip antenna length and frequency calculator:
  http://www.csgnetwork.com/antennagenericfreqlencalc.html
• Figure D-5 from the US Army Field Manual: http://bit.ly/2aQzllX
• Challenges and prospects in the telemetry of insects:
  http://www.ncbi.nlm.nih.gov/pubmed/24106908
• Federation of American Scientists – wave propagation: http://bit.ly/2b30MXh
• The relationship between frequency and wavelength:
  http://hubblesite.org/reference_desk/faq/answer.php.cat=light&id=72
• English names of the powers of ten (this is kind of fun!):
  http://www.isthe.com/chongo/tech/math/number/tenpower.html
• Electromagnetic notation:
  http://imagine.gsfc.nasa.gov/educators/gammaraybursts/starchild/page7.html
• Bone Fone – a wearable radio! I wore one of these for a ridiculous part of high school without suffering anything more than fashion damage. Because it was basically a low-power receiver (radio waves to ac power) that I wore around my neck for hours at a time, I wanted to use it as an example of safe, low-power, wearable active radio technology. But I figured cellphones made more sense. http://www.theatlantic.com/health/archive/2013/09/bone-fone-the-terror/279474/. 

Since you made it to the bottom, I hope you enjoy this bonus image. XKCD explains the spectrum as only they can!

DN2 Autopsy Report

We received a final autopsy report on DN2. The eaglet died as a result of Methomyl toxicity, although caffeine was also present. An analysis of DN2’s liver ruled out lead and mercury as the cause of death. It did not include information on the sex of the eaglet.

What is Methomyl?
Methomyl is a broad spectrum insecticide introduced in 1966 to kill a variety of insect pests. It is registered for commercial/professional use on sites including field, vegetable, and orchard crops; sod farms; livestock quarters; commercial premises; and refuse containers. It is toxic enough that products containing more than 1% Methomyl are not available for homeowner or non-professional application.

How were DN2 and Mom North poisoned?
While we don’t know for sure, Methomyl is sometimes used off-label to kill wildlife species that become problematic. 1% Methomyl products including Golden Malrin, Lurectron Scatterbait, and Stimukil are placed in sweet solutions, including caffeinated colas, to poison animals like raccoon that some consider pests and can cause damage to buildings and farm animals. Given the presence of both Methomyl and caffeine, it seems likely that Mom North found a Methomyl-poisoned dying or dead mammal and brought it to the nest to eat. It wouldn’t have taken much to kill DN2 or Mom North, since Methomyl is highly toxic.  Based on what we observed, Mom North was able to metabolize and recover from what she ate, but DN2 was not. While it is possible that the poisoning was the unintended consequence of a legal use of Methomyl, the caffeine suggests it was not.

For more about the problems of baiting wildlife with Methomyl, follow this link: http://www.sciencemag.org/news/2016/02/regulators-move-limit-wildlife-deaths-misuse-deadly-fly-killer

Is this legal?
It is not. While Methomyl and many other pesticides and insecticides are legal when used in a manner consistent with labeling, it is illegal to go off-label and use them in a manner for which they are not intended. Fly bait is legal when used according to direction and illegal used in any other way. There may be state and federal penalties for people caught misusing it, depending on state and federal law, and what species are killed.

What are you going to do about it?
We have already reported the incident to the Iowa State DNR and the US Fish and Wildlife Service, and will report it to the EPA and the manufacturer of the most likely culprit, Golden Malrin. We will also use our RRP website, Facebook and Twitter audience to help spread the message about misuse of Methomyl and let people know that they can petition their states to reclassify Methomyl fly baits as restricted products should they choose to do so. We would love to say that this was an isolated incident, but a quick search for “golden malrin raccoon” reveals just how widespread the practice is. Google it and join the discussion!

Do you know who did it?
No. There is a lot of variability in eagle home ranges. While immediate nest defense/core territories tend to occur within 100 square meters or so of the nest, hunting territories vary considerably.  One study documented bald eagle summer home ranges that varied from 3 square miles to 18 square miles depending on age, nesting status, and available resources. But other studies have found even wider ranges in nesting bald eagles, including 37 square miles for a pair in Louisiana. The landowners in the immediate vicinity of the nest have expressed their commitment to conservation.  With bald eagles searching and scavenging for food over a large area, there is no way to know exactly where it cam from. We are not an enforcement agency, but we have reported what we know to enforcement agencies.

We don’t believe that anyone meant DN2 or Mom North any harm. But people need to know that off-label poisoning kills unintended targets and can have serious legal consequences. We don’t believe that anyone meant DN2 or Mom North any harm. But people need to know that off-label poisoning kills unintended targets and can have serious legal consequences. This may also be a good day to check garages, basements, and storage sheds to see what noxious and toxic herbicides, rodenticides, and insecticides are on hand that have tragic consequences for wildlife, pets, and humans. Want something to replace those highly toxic chemicals? Check out the Bio-Integral Resource Center (http://www.birc.org/) and their list of least-toxic pest control products: http://www.birc.org/2012Directory.pdf. Even if you can't go completely toxin-free, you can reduce harmful consequences by using products correctly and choosing the least toxic option. You can help by sharing and spreading the word to prevent the unintentional killings of bald eagles and other animals.

Note that Methomyl is toxic enough that the Environmental Protection Agency (EPA) and Methomyl manufacturers have agreed to limit use on certain crops to reduce risks to drinking water: http://bit.ly/29yhNcY. EPA and manufacturers have also reached an agreement to stop making and selling some fly bait products and to add information to the label that clarifies the approved uses. EPA believes that these changes will reduce the illegal use of methomyl fly bait products which can kill wildlife, an issue that was reported to EPA by a number of states.

Are you an academic studying this issue? Please contact us by emailing amy@raptorresource.org.

Intervention at Decorah North Nest

As watchers at the Decorah North Nest know, female eagle Mom North brought some tainted prey into the nest on the afternoon of May 25th. She fed DN2, who promptly died, and ate some herself. Until we shut the cams off, horrified watchers saw a very sick Mom North struggling in the nest.

Neil Rettig and veterinarian Laura Johnson monitored the nest through a private channel. As the night passed, Mom North began to recover from whatever the prey had been tainted with. After she flew off the nest on the morning of May 26th, we knew we needed to make a plan to recover DN2. We wanted to autopsy the eaglet to determine the poisoning agent and prevent Mom from feeding DN2 to DN1 and killing DN1 as well.

The morning started with a call to Kike Arnal, who had climbed into the north nest last fall. Like Neil, he expressed some concern about going into the nest itself and recommended that we try to recover DN2's body with a hook or catchpole. Fortunately, Neil was available to climb. Several of us are versed in rope technique, but the North Nest is very tricky to access and Neil is the only one of us with tree spike experience, which he used to avoid potentially injuring the eagles with a crossbow bolt or line. While Neil, Laura, and Dave Kester made a plan, Amy Ries got busy working on the permit side of things.

Bald eagles are protected by a number of laws, including the Bald and Golden Eagle Act, the Migratory Bird Treaty Act, and the Lacey Act (introduced in 1900 by an Iowa congressman). It is highly illegal to trespass on an active bald or golden eagle nest or take, possess, sell, purchase, barter, transport, or export or import any bald or golden eagle, alive or dead, including any part, nest, or egg. The penalties are severe and may include a fine of $250,000 or two years of imprisonment, which is doubled for an organization. Should we be found to have broken the Bald and Golden Eagle Act, we could also lose our banding permits, which would end our banding program. While these laws may seem harsh, they have been an important part of returning the bald eagle to the American landscape, and we had no intention whatsoever of running afoul of them.

Amy contacted Deanne Endrizzi from the US Fish and Wildlife Service, and Pat Schlarbaum and Bruce Ehresman from the Iowa DNR. She explained the situation and outlined our plan. We would recover DN2 without going into the nest and take the body to Iowa State University's College of Veterinary Medicine for autopsy. The Iowa State DNR and the US Fish and Wildlife Service approved our plan very quickly and we were able to recover DN2's body yesterday afternoon. It is on its way to Iowa State University now. We don't know how long it will take for the results to come back.

Parent in tree

Dave retrieving DN2 from the catchpole

Why did you intervene?
We usually don't intervene in nest life. Wild birds survive and thrive in the presence of things that seem frightening and even awful to human watchers, including bad weather, predators, injuries, and aggression. Although humans found the death of DN3 appalling, it was completely normal eagle behavior. But poisoning is not nature taking its course and all parties agreed that intervention was appropriate and allowable in this case.

What happens next?
We are continuing to monitor the nest remotely, but the camera will remain off for live viewing for the time being. Mom has been in the nest with DN1, who has been fed and looks like a healthy, alert young eagle.

DN1 in the nest on the morning of May 27, 2016. 

Thanks to Neil Rettig, Dr. Laura Johnson, Dave Kester, Kike Arnal, John Howe, Deanne Endrizzi, Bruce Ehresman, Pat Schlarbaum, Allamakee county conservation officer Burt Walters, the US Fish and Wildlife Service, the Iowa Department of Natural Resources, Dr. Steve Ensley, and Iowa State University's College of Veterinary Medicine for their quick action and help. Your advice and experience were invaluable!

We've had some requests for the last video shot from the nest before we turned it off. This video shows an ill Mom in the nest, as well as DN2. If you find it disturbing to watch, please do not follow the link. I witnessed the event and found it very disturbing: https://youtu.be/g4ZC72FurzE

Proposed 30-year take of bald and golden eagles

As a lot of eagle fans are aware, the Fish and Wildlife Service recently announced a plan that would allow companies to kill federally protected bald and golden eagles for up to 30 years. The draft rule will extend the current permit duration of five years to up to 30 years, giving wind farms, power lines and other large projects license to injure, disturb or kill a limited number of eagles in exchange for commitments to avoid and mitigate harm.

The proposed rule has positives and negatives. Before we discuss them further, the public is able to comment on the rule until July 5th, 2016, although comments on the information collection aspects of this rule must be received on or before June 6, 2016. You can comment by going here: https://federalregister.gov/a/2016-10542 and pressing the green 'submit a comment' button on the top right of the page. We encourage people to read through some of the public comments prior to submitting their own.  The Fish and Wildlife Service also has comments and responses available on its website.

• Information Collection (comments must be received by June 6th): http://1.usa.gov/25bmjTV
• Permit Duration: http://1.usa.gov/1TyqPa3

Please read the rest of this blog for more information prior to commenting. 

History
The US Fish and Wildlife Service initially introduced a 30-year take rule in 2009. After reviewing the proposal, the American Bird Conservancy took the US Department of the Interior to court in 2014, stating that the Department of the Interior violated federal laws when it created a regulation allowing wind energy and other companies to obtain 30-year permits to kill protected Bald and Golden Eagles without prosecution by the federal government. The court agreed and the rule was invalidated in 2015. The Fish and Wildlife Service introduced a new rule in 2016, although it did not remove the 30-year take.

The current permitting program is voluntary: that is, companies can choose whether or not to join. The Fish and Wildlife Service hopes to bring a greater number of utility companies into the permitting program by changing the mix of penalties and incentives. Although the plan is not without negatives, more participation will yield more data about best practices for wind power and help determine how many birds and bats are killed by turbines.

Negatives

• The plan seems heavily predicated on mitigation, and there are only a few mitigation methods for wind energy that have been verified to reduce bird kills.
• Post-construction eagle mortality data is collected by paid consultants to industry instead of third-party experts, which is a conflict of interest.
• 30 years is a very long time to allow take of bald and golden eagles. Technology and bird populations can change much more rapidly than the proposed take period. 
• Permits remain voluntary. Companies can chose not to participate at all, although they will suffer legal penalties under the Bald and Golden Eagle Act and the Migratory Bird Treaty Act if they are found to have killed eagles. 

Positives

• The proposed regulations require applicants for permits with durations of longer than 5 years to conduct a minimum of 2 years of pre-application surveys. Surveys are currently voluntary. 
• Participation is voluntary and many companies currently opt out. Companies that join the permitting program will be under additional government scrutiny and are required to submit to a five-year review by the FWS, even though the 30-year take permit still stands overall. Companies found to be exceeding their take limits will be subject to additional penalties.
• The new rule allows for more flexibility in responding to local conditions and adopting new technologies. 

A permitted bald eagle take is problematic to most of us and, as the American Bird Conservancy stated,  "...‘green energy' isn't green if it is killing thousands of eagles and tens of thousands of other birds annually." [link to statement]. However, no form of energy is free of cost to wildlife and wildlands. Coal mining is environmentally destructive in many ways, nuclear energy has a waste disposal problem, birds and bats hit turbines, and electricity produced by all three is transmitted over hundreds of thousands of miles of electrical lines that come with their own collision and electrocution risks. At this time, the Raptor Resource Project supports properly sited wind power as a renewable energy source that helps reduce the threats posed to birds and people by climate change. But we also believe that wind farms can and should be properly sited and operated in ways that minimize harm to federally-protected species.  We will be following the American Bird Conservancy very closely on this issue and encourage those of you who are concerned about the issue to submit comments. Please remember to write clearly and constructively if you do. I have participated in public comment meetings, and incoherent or inaccurate comments are not taken seriously by rule makers.

I was just emailed this link yesterday: http://www.postbulletin.com/news/local/eagle-nest-puts-brakes-on-xcel-energy-wind-turbines/article_d9026393-996a-53f0-9b1b-3e4cef7310c5.html. The article is about an Xcel Energy wind project. Xcel Energy was the first company to sign a Memorandum of Understanding (MOU) with the Fish and Wildlife Service, which Bob was always very proud of. It shows the benefits that participating in these kinds of programs can yield, as well as the challenges of accommodating a bald eagle population with some very different behaviors and territories than those of America's historic bald eagles.

Resources

• Fish and Wildlife Service Rule Page (read about and comment on the rule)
• Greenwire: http://www.eenews.net/stories/1060036785 (an excellent article)
• American Bird Conservancy statement on the proposed rule: https://abcbirds.org/article/statement-on-new-eagle-rule/
• Threats to birds: https://abcbirds.org/threats/. This is an excellent, easy-to-read, and comprehensive review of threats, especially for those who want to know what they can do to help birds.

Decorah North News: DN3 has died

Eaglet DN3 died sometime yesterday. Why did DN3 die? While it didn't get nearly as much food as its larger siblings, it was still shooting poop yesterday, indicating that it had enough in its system to be pooping and excreting urates normally. However, DN3 may not have eaten yesterday and didn't eat much the day before that. It also didn't help that the weather was cold and damp. Mom and Dad North are brooding based on the older nestlings, who no longer require daylight brooding unless it is raining, snowing, or unusually cold. DN1 and DN2 have thermal down, but DN3's thermal down was just beginning to come in and it would have benefited from brooding.

We suspect there is no one cause for DN3's death. The six-day difference between DN3 and its oldest sibling resulted in insurmountable developmental differences, including dominance interactions that DN3 always lost given its much smaller size, a resulting lack of food, and a lack of brooding before it was really able to thermoregulate on its own. Had the weather been warmer, DN3 might have been able to survive even given the shortage of food and dominance interactions with the older two, but all three together were too much.

Are Mom and Dad North bad parents? No. Eagles don't fit neatly into our human ideas about what good parents are. The older two have been thriving under their care. From an eagle point of view, there is no purpose in caring for weaker young that are less likely to survive than healthy young. Personally, I would love to have seen DN3 survive and I was very hopeful up until yesterday afternoon. But as someone who loves and watches birds, I also need to accept that this is what they do. Humans don't make good parents for birds.

Why didn't we intervene? What happened at the North Nest is completely normal from an eagle perspective. It is well-documented that the youngest member of a three-nestling clutch can die, even though we haven't seen it in Decorah or Fort St. Vrain (eaglets have died because of hypothermia and illness at FSV, but those were very straightforward deaths and didn't involve just the youngest sibling). We haven't intervened in these situations in the past and will not moving forward.

Watching wild creatures doesn't give us ownership over them. The lives of 'our eagles' are truly their own and this was yet another example of how we differ from them. Juliet Lamb has some excellent perspective on the relationship between watchers and watched here: http://daily.jstor.org/wildlife-cams/


.

What is going on at the Decorah North Nest?

What is going on at Decorah North? The oldest eaglet, DN1, is displaying far more aggression than we are used to towards its siblings. It is upsetting to human watchers, especially since little DN3 takes much of DN1's biting, yanking, and twisting. However, we have also seen DN1 and even DN3 attack DN2. In most cases, the aggressive behavior ceases once the target submits, but we have seen biting and bonking continue past submission at least twice.

Why is this happening?
We don't know. Food certainly seems to be part of the puzzle, since we've often seen the eaglets act aggressively towards one another as they establish a feeding-related pecking order. However, we've also seen aggression break out in circumstances seemingly unrelated to food. For example, DN3 attacked DN2 at around 2pm this afternoon, giving it multiple bites, yanks and twists before DN2 submitted. The eaglets had all been fed well earlier today, so why the aggression? Perhaps differences in age and size also contribute to aggression. I would tend to believe that aggressive behavior is hard to stop once it starts, and I'm very curious whether we will see the drop-off in aggression here that we have seen in Decorah.

While siblicide is rare, aggressive behavior is common. It ranges from the relatively mild aggression seen in Decorah and at Fort St. Vrain to the biting, twisting, and yanking seen at Decorah North, Southwest Florida, and several other nests. I think this looks odd and frightening at least in part because Decorah has tended to lack extreme aggression. But Decorah and Fort St. Vrain could very well be outliers when it comes to eagle behavior. At this point, only the eagles know for sure.

Is DN3 growing normally?
It is very tough to tell with nothing but the two 'Cropzillas' to compare it to. DN3 is growing in thermal down to replace natal down, has gotten larger relative to the other two (seemingly overnight!), and is growing footpads. What we've been able to see of its beak has indicated a fairly regular size and shape in accordance with eaglet growth curves, and its talons are appropriately changing to black.

DN3 is just moving into the steepest part of its growth curve. The next five to seven days will give us a look at whether or not it is growing normally. We'll also look for developmental changes like nest wandering, attempting to stand, and tracking Mom and Dad outside the nest. DN3 has already been observed doing some of those things on warm days and we should see them more often as its thermal down grows in.

Is DN2 growing normally?
Yes, DN2 is growing and behaving normally.

Will DN3 survive?
DN3 is strong, gets fed, participates in nest aggression, and submits appropriately. The eaglets tend to fight with their beaks instead of their talons and, while the aggression looks frightening, DN3 hasn't been badly injured. It is rapidly growing in thermal down, which will help protect it from cold weather and aid nest exploration. Fighting is very hard to watch, but generally rare when one compares the time spent fighting with the time spent laying around the nest and eating.

There are no guarantees, but siblicide is uncommon and DN3 is much stronger than it seems. It often comes back with its own beaking, displaying its own fierceness, or can be seen afterward cuddling up to a former aggressor. We are hopeful it will survive and even thrive as it grows...but again, there are no guarantees with wildlife.

Will you intervene?
Absolutely not. We might consider interfering if the situation were human-caused, but these behaviors are completely normal from an eagle perspective. If we rescued every eaglet we were concerned about, there would be no wild eaglets left to watch. It is very important to keep eaglet behavior in perspective. For the most part, the parents have acted according to our expectations: feeding, interacting, brooding, and in general caring for their family. While the eaglets fight with one another, they spend more time cuddling, eating, and sleeping. While the fighting is upsetting to watchers, none of it is out of line or outside the parameters of normal eagle behavior.

In summary, the worst may happen but we are not giving up on DN3. The next five to seven days will tell us a lot more about its growth. It looks like we are starting to get pinfeathers on DN1, which means its growth will start slowing as feathers take over. While we have never seen this level of aggressive interaction in Decorah, eagles have survived it at other nests. We remain hopeful.

Kay from SOAR also provided some feedback after she was approached about the situation. She agrees that the situation "looks" terrible but that at this developmental stage of the eaglets they don't have a huge amount of strength in their beak.  Right now, those beaks are something like pointy salad tongs. Hopefully all three eaglets will grow well and this will not be a concern for much longer.  

Decorah North: DN1, DN3, and today on the nest

Watchers of the Decorah North Nest got quite a shock today after DN1 went after DN3 with a ferocity we haven't seen at any of the bald eagle nests we watch. It looked liked this:

• Mom North lands on the nest, chasing away a sparrow that was stealing straw from the nest. DN1 and DN2 are huddled together at about 7:00 on the left side of the nest, while DN3 is laying at about 4:00 on the right side of the nest.
• Both eaglets rise to a sitting position.
• DN1 dominates DN2, pecking and pulling on DN2's left wing. DN2 submits and DN1 stops.
• DN1 shoots poop, staying at roughly 7:00..
• DN3 sits up and walks over to the turkey wing at about 3:00, where it appears to be look up at Mom. Keep in mind that the eaglets are walking on their tarsi, not their feet.
• DN1 walks from 7:00 to 3:00 and begins a dominance interaction with DN3. In addition to pecking, DN1 bites and pulls on DN3, who submits. 
• As DN3 submits, it rolls against DN1, scraping DN1 with its talons in what appears to be an accident.
• DN1 resumes the dominance interaction, pulling and biting at DN3's wing and body and flipping DN3 over. DN3 remains in a submissive posture.
• DN1 pulls DN3 up by the 'scruff' of its neck four times
• Mom North, who has been watching the entire interaction, walks over and looks at DN1.
• DN1 ceases the interaction, although we don't know to what degree Mom North interfered with it. Was DN1 ready to quit given the lack of a response from DN3, or did Mom's arrival distract DN1?

Following this event and subsequent battles, the ugly specter of siblicide - one sibling killing another - leapt to everyone's mind. So how common is siblicide in bald eagles? Sources disagree, with some referring to it as relatively common (University of Nebraska, American Eagle Foundation) and others calling it fairly rare (Hornsby). It hasn't yet occurred at any of our cams - not in Decorah (since 2008), not at Decorah North (since 2016), not in Fort St. Vrain (since 2003), and not during the one year we were able to watch Eagle Valley (2013). Our nests have different parenting 'styles', levels of food availability, surrounding environments, and nest invaders, but to date all eaglet fatalities have been caused by hypothermia, predators, and suspected disease. Why did DN1 take after DN3 and (to a lesser degree) DN2 today? We don't know, but as tough as it was to watch, it wasn't especially prolonged and didn't lead to death.

People also worried about a lack of food deliveries to the nest. While we don't know why parents don't pile up the pantree here as they do in Decorah, birds of prey (even young ones) can go a long time between meals. The eaglets remain healthy, alert, and pooping, which tells us that their digestive systems are working just fine. They are moving around the nest, interacting with one another and with parents, and showing interest in their surroundings. I'm sure they would like a meal, but they aren't starving yet and won't be for some time.

Several people referred to Dad and Mom as 'bad' parents. Again, different nests have different parenting styles, but eagles don't divide neatly into human narratives of good and bad behavior. It is a warm day, the young don't need brooding, and either Mom or Dad have been perched nearby much of the day. They are taking care of their young as they see fit, and we know from studies on human-raised birds that young birds have very different needs than young humans.

We've also been asked if we will rescue DN3. Absolutely not. We might consider interfering if the situation were human-caused, but what happened today was completely normal from an eagle perspective. If we rescued every eaglet we were concerned about, there would be no wild eaglets left to watch. It is very important to keep today in perspective. This is one of the first days we have seen a lot of concern about Decorah North. For the most part, the parents have acted according to our expectations: feeding, interacting, brooding, and in general caring for their family. It is also the first day - the first time - we have seen that level of aggressive interaction in one of the bald eagle nests we watch. But none of it was out of line or outside the parameters of normal eagle behavior. If eaglets died after a warm day with just one meal, we wouldn't have eagles to admire and worry about.

In 2011, a follower sent me a lovely watercolor painting of the fledglings at the Decorah nest. It said "You are braver than you believe, stronger than you seem, and smarter than you know." It remains a favorite artwork of mine and I often think of it when I am concerned about the eagles. As anthropomorphic as the painting may be, eagles are truly stronger than we think and often smarter than we know. As much as we love them, they are only their own and what we saw today was simply part of the way they live their lives.

Note: Hornsby follower gzebear compiled observations from 147 nests checked in an 8 year period and found only a 2% incidence of siblicde in hatches of 2, and 3.8% in hatches with 3. Follow the link to read gze's data, references, and additional comments from contributors to the thread. I think it might be time to revisit the whole subject of three-egg versus two-egg clutches. How common is one versus another? Are there regional differences? Is it an inheritable trait? Do we have more three egg clutches than we used to? It's off-topic here, but I subject that interests me quite a bit.

Eaglet Growth and Development: Week Four

D24 and D25, April 25, 2016

D24 is 28 days old today, while D25 turns 26 days old. At this point, feather growth is starting to overtake structural growth as the eaglets approach the half-way point in the nest. Pinfeathers emerged this week, growing at an astonishing rate as they poked out from their keratin sheaths along the edge of the eaglets' wings. Feathers also started to emerge along their backs - the 'cloak' - and sprout from their tails. As beak, leg, and footpad growth began to slow, wing growth sped up, leaving the eaglets with noticeably longer, larger wings by the end of week four.

We also saw changes in behavior. Although the eaglets will continue to compete for food, baby bonking has ceased. This always makes me wonder what functions it serves. We know it strengthens muscles, aids coordination, and helps improve eyesight. Does food competition lead to greater food intake, helping to fuel an eaglet's rapid growth? Does it lay the ground for future social interaction, which includes plenty of body language, vocalization, and dominant/submissive interaction? Does it give parents information about an eaglet's overall heath, or help prompt provisioning? Or is it simply replaced by a new suite of physical behaviors as the eaglets begin to explore the nest and enter the next phase of nestling life? Bonking may have ended, but the eaglets are starting to play with sticks, move towards a full stand, and expand their explorations of the nest. They've also begun noticing the area around the nest, tracking with Mom and Dad as the adults pay attention to the outside world.

So what can we expect to see in week five? Watch for an explosion of dark feathers, leading to an evenly mottled grey and white appearance some time in the next week. The eaglets will begin standing and walking, leading to many mouse clicks as we try to shoo them back to the center of the nest! We may see them begin to tear their own food and we will get to see them 'play house' as they begin moving sticks around themselves and with Mom and Dad. If past years are any judge, Mom and Dad will give them plenty of materials to work with as they pile up the crib rails with larger, heavier sticks!

We've talked a lot about physical changes. We are also entering a period of rapid developmental changes as the eaglets acquire new skills and grow feathers. The eaglets will play cooperatively and competitively, learn to stand, walk, and tear food, and begin moving their wings. Following the appearance of Mom's teakettle whistle, I'm waiting for baby vocalizations to turn into juvenile screes for food! I'm looking forward to watching D24 and D25 move into the next phase of their lives as feather growth takes over from body growth and greater mobility leads to changes in behavior.

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. Thermal down starts growing at about ten days, juvenile deck feathers at about 20-23 days and juvenile flight feathers at about 27 days, but 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.

So where is our cortical homunculus in weeks 4-5? I'd tend to think that legs, feet, and wings are accelerating in importance this week, leading important behaviors like standing, tearing, and flapping! I also wonder what impressions are being made now that they are beginning to pay attention to the outside world and have moved from playing with grass to nibbling at larger, heavier sticks. The nest and eagles always have more to teach us!

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

• Eaglet weight and growth is based on Gary Bortolotti's work with eaglets at Besnard Lake in Canada. It is possible that our eaglets are a little smaller than his, since Bald eagles get bigger the farther north one travels: a phenomena known as Bergmann's Rule. Bortolotti's paper makes for interesting reading and provides a great look at the work involved in field science. Citation: Physical Development of Nestling Bald Eagles with Emphasis on the Timing of Growth Events, The Wilson Bulletin, Vol. 96, No. 4 (Dec., 1984), pp. 524-54. https://www.usask.ca/biology/bortolotti/pubs/wb96-4-524-542.pdf
• Mouseunculus: http://phenomena.nationalgeographic.com/2013/07/24/mouseunculus-how-the-brain-draws-a-little-you/
• Homunculus: http://io9.com/5670064/how-your-brain-sees-your-body-meet-the-cortical-homunculus
• Input from Bob Anderson, who imparted much wisdom and information before he passed.
• RRP moderators and their calendars, lists, books, charts, and personal observations.

Eaglet Growth and Development: Week Three

04/13/16: Decorah Nest	04/13/16: Decorah Nest
04/19/16: Decorah Nest	04/19/16: Decorah Nest

D24 is 22 days old today, while D25 turns 21 days old. In the past week, the eaglets' footpads and talons have grown, their feet and legs have yellowed, and their talons have turned almost entirely black. Their mohawks have become more apparent as they shed their white natal down, which disappears from the head last. Almost every time I checked in, the eaglets were either eating or recovering from a meal. Their crops bulged so heavily at times that it was hard to believe they could sit up! They also had a fine buffet to chose from, including trout from the hatchery (look for finer scales and a front pointing mouth with thin lips), sucker (look for rougher scales and a bottom pointing mouth with fleshy lips), rabbit, muskrat, and even a mink.

Eaglets spend roughly 75-80 days in the nest, so we are a little under a third of the way to fledge. Most birds of prey seem to spend roughly the first half of nest life gaining weight and growing structural features like footpads, talons, toes, and beaks. While some structural growth may occur later on, the second half of nest life is dedicated to feathers and wings as feathers replace down and wings lengthen.

This week we were treated to a lot of eating and sleeping, but big changes are on the way! Pinfeathers started growing out late in week three and poop went from little slices to big spatters as the eaglets got better at sitting up, bending over, and shooting poop! What else can we look forward to in the coming week?

• The eaglets should start standing on their feet. This will change nest exploration and enable them to really get to work on the Poopcasso tree!
• Natal down mohawks will vanish and dark deck feathers will poke through the eaglets' natal down at an astonishing rate.
• Still enclosed in their keratin sheaths, eaglet pinfeathers will grow longer. 
• We may be treated to the beginning of wingercizing sessions! Once the eaglets can stand, they can really begin exploring their wings. 

By the end of the fourth week, the eaglets should be standing well and may be starting to walk and tear their own food. I have no doubt that many of us will be mouse-clicking, shoeing, and blowing to get inquisitive eaglets back into the center of the nest as they widen their explorations and begin broadening their horizons! 

While we've been making guesses at gender, the weight of the two sexes begins to separate as females gain weight faster than males.  Sex takes over from age as a size determinant around 50-60 days. But cameras can be tricky and clutches can have large males and small females or be all one sex, making ID impossible without measurements or a genetic test. We'll have a lot of fun seeing if size conforms to our observations based on what we have seen of beak size, commissure extension, and other traits, and I can hardly wait for food tearing and wingercizing!

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. Thermal down starts growing at about ten days, juvenile deck feathers at about 20-23 days and juvenile flight feathers at about 27 days, but 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! I'd tend to think that legs, feet, and wings are starting to 'light up' this week, leading important behaviors like standing, tearing, and flapping!

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

• Eaglet weight and growth is based on Gary Bortolotti's work with eaglets at Besnard Lake in Canada. It is possible that our eaglets are a little smaller than his, since Bald eagles get bigger the farther north one travels: a phenomena known as Bergmann's Rule. Bortolotti's paper makes for interesting reading and provides a great look at the work involved in field science. Citation: Physical Development of Nestling Bald Eagles with Emphasis on the Timing of Growth Events, The Wilson Bulletin, Vol. 96, No. 4 (Dec., 1984), pp. 524-54. https://www.usask.ca/biology/bortolotti/pubs/wb96-4-524-542.pdf
• Mouseunculus: http://phenomena.nationalgeographic.com/2013/07/24/mouseunculus-how-the-brain-draws-a-little-you/
• Homunculus: http://io9.com/5670064/how-your-brain-sees-your-body-meet-the-cortical-homunculus
• Input from Bob Anderson, who imparted much wisdom and information before he passed.
• RRP moderators and their calendars, lists, books, charts, and personal observations.

Thank you to our volunteers!

This week is National Volunteer Appreciation Week! I wanted to take the time to thank all of our wonderful volunteers for everything they do for us!

Our Chat and Facebook Mods dedicate an extraordinary amount of time to providing a fun, educational chat. In addition to time spent online with watchers, they dedicate themselves to learning everything they can about bald eagles and their habitat, help keep me informed of important or extraordinary events, let me know when technology is going wrong, and bring their own ideas to bear on tools and content for followers! Our sites would not be what they are without them.

Our  Camera Operators and Video Makers share life in the nests with us. They give us extraordinary close-ups, interesting moments, and tours of the areas that shape the lives of the birds we watch. Thanks to them, we get to see and relive important events and cuteness overload close-ups, even when we aren't able to watch live!

Our Landowners share their wildlife and resources with us. We would not be watching eagles if they weren't willing to let us do so. Those with falcons on their properties watch nests, provide helpful information, and let us on to their land to band, survey, and put up boxes. They have been a critical part of peregrine falcon recovery!

Our Board is working on long-term goals and strategies. We would not have N2B or Decorah North without their direct help, and it has been wonderful to work with them as we do things now and prepare for our future.

Volunteers, I appreciate their dedication and talents more than I can say. As Bob would say "You ROCK!" Thank you for all you do.

Amy

Eaglet Growth and Development: Week Two

D24 and D25: 04/04/16

D24 and D25: 04/12/16

D24 is 15 days old today, while D25 turns 13 days old. The week-old difference between these two photos is striking. In their second week of development, the eaglets grew larger, gaining roughly two pounds between April 4th and April 12th. They experienced rapid growth in features like beaks, culmens, and footpads, replaced their white natal down with thicker grey thermal down, and began exploring the nest. Although they aren't yet standing on their toes, they are able to sit up - way up! - for feeding and shuffle around on their metatarsi.  Their eyes are wide open and fit more comfortably in their eyesockets, features like brow ridges are beginning to appear, and their legs and footpads are yellow, not pink. 

Gary Bortolotti wrote that bald eagles might gain more weight per day than any other north American bird, although the majority of their weight gain occurs within the first 30-40 days. This rapid weight growth is fueled by their nutrient-rich diet of meat. Over the past week or so, we watched the eaglets chow down on fish, roe (fish eggs), venison (aborted fetal deer), rabbit, squirrel, something that might have been a muskrat, waterfowl, and several other birds. D24 became proficient enough at shooting poop to christen the Poopcasso tree on April 5th, while both eaglets got in plenty of tussling and bonking play, alternately hitting, submitting, and quitting to cuddle in the nest cup, grow, and wait for more food to arrive.

Watchers have been asking why the Fort St. Vrain eaglets began wandering the nest so much earlier than the Decorah eaglets. While we don't know for sure, we suspect that temperature played an important role. Fort St. Vrain experienced unusually warm temperatures in late March and early April, and the leaves hadn't unfurled to provide shade for the nest. Cold is a challenge to eaglets under 10-15 days of age, but so is heat! With little ability to control body temperature and no way to lose heat except by panting, the eaglets did their best to retire to what little shade tree limbs and the nest itself offered. Once in the shade, they sprawled out as much as they could. Mom did her best to provide shade for the eaglets, moving from one to another and standing between them and the sun.  As alarming as it was to viewers, Mom's ploy worked and we didn't see quite as much wandering, at least for a few days, after the weather cooled down. 

In the week to come, we can expect (continued) rapid growth in footpads, talons, and legs. Beak growth will rapidly slow as the eaglets' beaks approach adult size and we may see dark juvenile feathers start to sprout from their grey down. Overall weight and height gain will continue, most  likely reaching their steepest curves some time this week. By the end of the week, our little bobbleheads at Decorah and Fort St. Vrain will be almost a foot tall, while the eggs at Decorah North should begin hatching! 

Watchers have observed that different nests seem to have different 'parenting' styles: i.e., Dad may be more present at one nest than another, food may come in more or less regularly, and eaglets might spend more time alone. Many things influence nest life, including weather, temperature, food availability, predators, and the presence of other adult, sub-adult, and juvenile bald eagles. While eaglet growth and development occurs along a fairly predictable trajectory, local conditions can change the timing of events - something we've seen in Decorah, Fort St. Vrain, and the year we watched Eagle Valley. We are looking forward to hatch at Decorah North!

---

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. Thermal down starts growing at about ten days, juvenile deck feathers at about 20-23 days and juvenile flight feathers at about 27 days, but 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! I'd tend to think that visual acuity suddenly 'lit up' this week, leading changes in coordination as the eaglets began sitting up and moving around.

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

• Eaglet hatch weight is based on Gary Bortolotti's work with eaglets at Besnard Lake in Canada. It is possible that our eaglets are a little smaller than his, since Bald eagles get bigger the farther north one travels: a phenomena known as Bergmann's Rule. Bortolotti's paper makes for interesting reading and provides a great look at the work involved in field science. Citation: Physical Development of Nestling Bald Eagles with Emphasis on the Timing of Growth Events, The Wilson Bulletin, Vol. 96, No. 4 (Dec., 1984), pp. 524-54.https://www.usask.ca/biology/bortolotti/pubs/wb96-4-524-542.pdf
• Mouseunculus:http://phenomena.nationalgeographic.com/2013/07/24/mouseunculus-how-the-brain-draws-a-little-you/
• Homunculus: http://io9.com/5670064/how-your-brain-sees-your-body-meet-the-cortical-homunculus
• Input from Bob Anderson, who imparted much wisdom and information before he passed.
• RRP moderators and their calendars, lists, books, charts, and personal observations.

Is the last egg going to hatch?

The last egg in the Original Decorah nest

As of this morning, the unhatched egg in Decorah is somewhere between 49 and 42 days old. Can it still hatch? Eagle eggs have hatched as late as 44 days after they were laid. If this is the last egg, we still have roughly two days in which hatch could occur. However, eggs have never hatched this far apart in Decorah before. Given the dates, it is possible that we've seen the hatch of eggs number two and three instead of eggs number one and two as we initially assumed. Roughly 3% to 12% of bald eagle eggs fail to hatch based on the studies I read, although some sources put the number a little higher, at 10% to 25%.

So why wouldn't the egg hatch? Eggs fail to hatch because they are either infertile or nonviable. Infertile eggs occur when the ovum is not fertilized before it begins its journey down the female's oviduct. We know that bald eagles copulate frequently before and during egg laying, which helps assure that sperm is present in the right place (the infundibulum) at the right time (when the ovum arrives).  Since female birds don't have a way to reject or stop the egg-laying process once it begins, incomplete, poorly timed, or insufficient copulation can result in unfertilized eggs.

A nonviable egg occurs when an embryo fails to develop properly and dies. This is mostly likely to happen within the first three days of incubation (embryonic organs fail to develop) or the last three days immediately prior to hatch (major organ failure becomes apparent or hatch starts but cannot be completed). Non-viability can happen for a number of reasons, including:

• Insufficient incubation. Incubation is fairly complex! Eggs must be kept at the proper temperature and humidity and turned regularly. Freshly laid eggs can spend time in the zone of suspended development (roughly 28.4 to 80.6°F) with no harm to the egg or embryo, but eggs must remain between about 99 and 104°F once development starts. Time off the eggs regulates humidity and helps keep pores from clogging. Turning or rolling the eggs prevents the developing embryo from sticking to the side of the egg, brings it into contact with fresh 'food' and important nutrients supplied by the yolk and white, and assures proper development of the membranes that exchange gas and protect the embryo from contaminants. 
• Piercing or cracking of the shell. If the egg shell is pierced or cracked before the embryo is fully developed, it will die. This can happen if the egg is jostled too vigorously, stepped on, or damaged or destroyed by an intruder - something that has been documented in many species of birds. 
• Insufficient nutrition. Given all that we've seen the eagles eat, this doesn't seem to be especially likely in Decorah. But if a female bird is insufficiently nourished before she begins laying eggs, her eggs won't have the nutrients needed to nourish the developing embryo. 
• Bacterial or chemical contamination. Although the embryo is protected by a shell and layers of membrane, contaminants can sometimes make their way into an egg and impede or kill the embryo inside it. 

We aren't going to attempt to retrieve the egg if it doesn't hatch - at least not while the birds are in the nest. Without opening the egg, we have no way of knowing why it failed. On one hand, the eagles spent a surprising amount of time off the first two eggs. On the other, studies in some species of birds indicate that infertility is more common than non-viability. Infertility is also more likely to prevail in first and last-laid eggs, which is unsurprising given the importance that timing plays in fertilization. 

What will happen to the egg? Different species do different things, but bald eagle eggs are commonly buried under layers in the nest, where they presumably break and decompose. Eggs may also be pierced or trampled as siblings grow and become more active. We will look for the egg if we go into the nest this fall. If we find it intact, we will turn it over to the USFWS for study. 

Will the next eaglet to hatch be called D26 or D27? This is confusing to followers who have seen nothing but production success. However, peregrine falcons aren't always successful and we don't count production until after banding. A falcon that makes it to fledge but dies soon after is still considered in production counts, but a falcon that dies before banding is not. If this egg doesn't hatch, the next living eaglet will be called D26. 

It's hard to believe that we could have an unhatched egg after so many years of success. How many times have we been worried about something only to have it all turn out right? But eggs don't always hatch and even excellent parents like our Mom and Dad experience failure. I'm glad we have D24 and D25 to watch this year and I look forward to studying the dynamics and rearing of two siblings, even though I wish there were three.  If we have a chance, we'll retrieve the egg for inspection and we will also review the video record to determine how much time was spent off the first egg.

Note: While I included contaminants on the list of things that can cause eggs to fail, my guess would be that this egg failed due to infertility (statistically more likely according to what I could find) or incubatory failure due to cold exposure.