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!

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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.

Eaglet Growth and Development: Week One

Newly hatched D25, March 31st 2016

D24 is three days old today, sibling D25 is not quite a day old as I write, and D26 is still inside the egg. What can we expect in the first week of watching?

Weight Gain!
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.

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.

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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:

• 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.

How and Why to Donate to the Raptor Resource Project!

What does the Raptor Resource Project do? We are a 501c3 that specializes in the preservation of falcons, eagles, ospreys, hawks, and owls. In addition to bringing you the Decorah Eagles, Great Spirit Bluff Falcons, and other birds of prey, we create, improve, and directly maintain over 50 nests and nest sites, provide training in nest site creation and management, and develop innovations in nest site management and viewing that bring people closer to the natural world. Our mission is to preserve and strengthen raptor populations, expand participation in raptor preservation, and help foster the next generation of preservationists. We are asking for donations today to support our work. You can donate online at PayPal by following this link, or you can mail a check to:

The Raptor Resource Project
PO Box 16
Decorah, IA 52101

As a nonprofit environmental organization, we depend on donors, research, and our other programs for our entire budget.  In the upcoming year, we plan to:

• Establish a wild Philippine eagle camera. We are waiting for a report from Cornell on how to proceed. At this point, our costs are unknown.
• Continue our collaborative raptor nest-box, trapping, and monitoring programs, including banding at all of our peregrine falcon sites in Minnesota, Wisconsin, and Iowa. If the weather holds, this will be a banner year for us. I believe we could end up banding 70 or more falcons!
• Upgrade at least three more sites to high definition digital cameras. We would like to do more if we can! 
• Continue to provide one of the world’s largest public wildlife education programs to countless classrooms through our unequaled Ustream channels, interactive chats, facebook page, and blog.
• Hire a full-time director. Our current director is volunteering all of his time to lead the Raptor Resource Project. He’s done a wonderful job and we would like him to work for us full-time. He was selected by Bob and has been absolutely critical in carrying Bob's legacy and plans forward. 
• Explore partnerships with schools and other organizations to benefit wildlife and land preservation in the Driftless Area. At present time, we are working with Hoo’s Woods Raptor Education and Rehabilitation Center and several other partners on a kestrel poster project.  Bob had become very interested in kestrels and we are interested in re-launching that project.
• Build and deploy online tools to develop appropriate tools to easily capture and share data from our sites and other sites.

With our volunteer director, our current costs hover around $118,700…but we will need to raise more money to bring our director on full time. In 2015, our expenses looked like this:

• $55,000 for staff and contracts. In 2015, we incurred extra expenses for our N2B build and two camera installs: one at N2B and one at Decorah North Nest. These were intensive projects that required a lot of help. The N2B camera installation alone took nine people five full days of work from dawn past dusk. Five or six volunteers also showed up to help at will.
• Camera installations – a computer and peripherals, cameras and peripherals, labor and materials, high speed internet, caretaker/rental costs, and audio systems - cost $17,500 per site, for a total of $52,500 in 2015.
• Supplies – primarily cable, tools, climbing equipment, banding equipment, bands, installation hardware, maintenance equipment, and lumber – cost around $2200 annually.
• Other/Miscellaneous costs around $9,000 annually. This category includes gasoline, electricity, travel-related costs, equipment fabrication, and propane so we can heat the shed!

Our income is generated entirely by donations from viewers of our various cams, and we sincerely appreciate your generosity and support of the Raptor Resource Project mission. Would you please help us make a difference with your donation?

Thank you so much for your support and we hope you enjoy watching in 2016! Go eagles and falcons! As we celebrated D24 yesterday, I couldn't help but think of Bob, the person who started it all. A few links:

• D1's capture and Bob's happy dance! https://youtu.be/CDetJJt4V5U
• A celebration of Bob's life: https://youtu.be/QMPbzWYKdMQ

Do bald eagles delay incubation?

2014, Egg #2. Temp with windchill: -40F.

Do bald eagles delay incubation? It wasn't an a question we've thought about much, since bald eagles in Iowa usually lay eggs in temperatures under - sometimes well under - freezing! However, this year was quite a bit warmer, and the eagles in Decorah and Fort St. Vrain seemed to spend more time off the first two eggs than we are used to.

The question seems pretty cut and dried. After all, peregrine falcons delay full incubation very consistently until the third egg in a four-egg clutch, and the fourth egg in a five-egg clutch. In cold years (2013, 2014), we tend to experience higher losses than in warm years, since eggs one and two can freeze and die prior to the beginning of full incubation. However, it isn't that simple with bald eagles and many other birds.

2016, Egg#2: Temp no windchill: between 25-40F.

According to Professor Jim Grier, birds often start incubation slowly or gradually when temperatures aren't in the freezing range. Freshly laid eggs can spend a lot of time in the zone of suspended development (roughly 28.4 to 80.6°F or -2°C to 27°C) with no harm to the egg or embryo. While I don't have storage times for bald eagle eggs, Wikipedia tells me that the freshly laid eggs of domestic fowl, ostrich, and several other species can be stored for about two weeks when maintained under 5 C. That is quite a bit longer than the time between eggs one and two in a bald eagle nest!

Temperature aside, why do some birds begin incubating immediately? In a blog on the subject, David Hancock discussed two theories of immediate incubation: one, to protect eggs from marauding ravens and other predators, and two, to assure the survival of at least some young during periods of food scarcity. In the last case, the 'strategy' assumes that it is better to have one or two surviving children than no surviving children at all.

However, there are more benefits to delaying incubation so eggs hatch closer together: indeed, the survival of many waterfowl depends on it since adults leave the nest 24-48 hours after hatch begins, whether all of the eggs are hatched or not. Perhaps most importantly, delaying incubation helps assure that rapidly growing young are in the same stages of development. In the presence of an abundant food supply, more young will likely survive when incubation is delayed, since there will be less variation in size and ability between older and younger siblings, and food should be shared more equitably as a result.

Professor Grier pointed out that the nature (if not essence!) of biology is variation. This caused me to think back on eagles and monogamy. When we first started this adventure, everyone 'knew' that eagles were monogamous and mated for life. A new mate would be taken only if the old mate died. Remember when that was true? But once we really started looking, eagle relationships turned out to be more complicated. While many eagle couples appear to be monogamous, we've also documented extra-pair copulations, eagle 'divorce', polygyny, and polyandry.

The same is undoubtedly true for incubation. Professor Grier wrote that he would expect variation among different pairs of bald (and other eagles) in how much time they spent off the egg(s) both at the start and as incubation proceeded, as well as under different conditions such as temperature, humidity, and precipitation. We've certainly seen that in Decorah. In 2014, February's mean temperature was 9.4F - the coldest in 20 years of recording! Under those conditions, Mom and Dad incubated almost constantly. But in 2012, February's mean temperature was 27.8F - not the warmest ever recorded, but quite close to it. As indicated by video footage and all of the blogs and posts we did on the subject, Mom and Dad spent much more time off the eggs in 2012 than they did in 2014. While weather is clearly a factor, David Hancock noted timing variability between rural and urban bald eagles, and speculated that the presence of predators might make a difference in whether incubation was delayed.

The world is not a static place. Animal populations fluctuate as food supply, weather, and disease cause cycles of booms and busts. High populations and/or low food supplies can result in massive dispersals or irruptions as birds compete for territory and food. Populations may adopt different behaviors at different levels of density and food abundance, perhaps becoming less aggressive in a situation where neighbors and food are both in high supply. Everything changes over time: given a large enough timescale, the continents themselves flow like water. In that light, it is no surprise that eagle incubatory behavior might vary, or that eagles might adopt different behaviors as their population and/or the world around them changes.

So philosophy aside, can we really answer the question of delayed incubation in bald eagles and other birds? That's a tough one. The onset of incubation doesn't seem to involve timing in most species of birds, since they appear to be responding more to external factors than to an internal clock. This makes it hard to define what exactly 'delay' is for most birds. If I'm staying off my eggs because it is warm out, am I really a delayed incubator? If I almost always incubate right away because I lay eggs in sub-zero temperatures, am I really an immediate incubator?

Short answers are often necessary in our instantaneous and highly-connected world, so here is mine: "Bald eagles may or may not begin incubation immediately after the first egg is laid, depending at least in part on local factors that include temperature, humidity, precipitation, and predators. Apart from that, bald eagles exhibit variability: that is, not all pairs act the same way, even given the same or similar situations. There is more to learn, so keep watching, keep documenting, and trust the eagles!"

I'm going to close by quoting Professor Grier again: "The nature (if not essence!) of biology is variation." In my experience, almost every time we say a species always does this, or never does that, the species proves us wrong! Onset of incubation and mating systems are just two more examples of that.

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Our ideas about birds have been shaped by how we observe them. Professor Grier pointed out that in the past, normal incubation details for various birds were studied from blinds, long-term and time-lapse photography, and with electronically telemetered artificial eggs, nest thermometers, treadles or scales to measure adult presence on the eggs. He wrote: "Eagle cams provide a whole new opportunity to observe and study traits such as incubation behavior (by individual parent, gender, total time, and under various environmental conditions) on increasing sample sizes of birds under undisturbed conditions." In other words, nest cams give us an unparalleled opportunity to observe large populations of birds in the wild, relatively free from human interference. Who knows what we will find, or what theories and beliefs will be challenged? We've got the cameras in the field. The next step is to develop appropriate methodologies and tools to enable large scale data collection across species and populations.

Thanks to the following for helping me learn about this subject.

• Personal communication, Professor James Grier. Any mistakes I made in interpreting his email are my own. 
• Personal communication, Bob Anderson. Bob used to tell us that eagles were pretty smart, but peregrine falcons were only about as smart as garter snakes. Even though he loved falcons, he believed that their lower intelligence made them less variable in their response to external stimuli. While that was outside the scope of this blog, I will return it later on.
• David Hancock's blog on Bald Eagle Laying and Hatching Sequences

Thoughts on the sub-adult nest-intruder

We had an intruder at the Decorah North Nest on March 13th. While Dad was in the nest incubating the pair's single egg, a roughly four-year old female eagle perched on a limb right next to the nest tree. He responded by covering the egg, softly vocalizing, and ruffling his feathers. The whole encounter lasted about fourteen minutes.



I was intrigued by Dad's soft vocalizations. Why didn't he call a little louder? I went to our panel of eagle experts for an answer. Jim Grier and Brett Mandernack both provided insights into Dad's behavior. Note that neither Jim nor Brett referred to the eagles by title (Dad) or sex. Those additions are my own.

Jim has extensively studied eagles in Ontario and along the Mississippi River Valley. He noted that the density of eagles is getting so high that it might be changing eagle "society" and interactions, or bringing out behaviors that don't occur in lower density [and perhaps limited food-base] situations.While we don't think of the Decorah North Nest as urban, bald eagles along the Mississippi river and its environs are urbanizing as the population density grows. Our initial ideas about the lonely majesty of the bald eagle may have come from observing lower-density populations in a landscape much less impacted by human beings.

Jim explained that the soft vocalizations sound more like typical young- or mate- calls made at close range between young and parents or between mates (as in food-begging by young toward adults or females toward males). He also pointed out the direction of Dad North's gaze. Dad North didn't spend much time looking at the eagle on the branch, almost as it he was familiar with her. To quote:

"Direct" gaze can include both truly direct, focused straight at -- with both eyes and holding the gaze -- or what I call indirect-direct, mostly a side-ways look with occasional looking away and often with raised hackles, all of which is the prelude to an attack if an intruder doesn't back off. When an eagle is presented with a new individual that it doesn't know but which it is not particularly concerned about, it will "study" the new individual, looking directly at it and looking at different parts of its body. Then it will look away briefly, then look back and study it some more, and alternate with increasing lengths of time looking away and shorter periods of gazes ... until it becomes "familiar" with the new individual and then, subsequently, usually only glance occasionally at the individual but mostly seeming to ignore the familiar bird nearby. 

As upset as Dad might look to us, his indirect gaze indicates he might not have been especially concerned with the intruder. There was just one brief threat-bout toward the bird on the branch when he stood up to bring in his wings and change position. Jim suggested that there could be some mutual extra-pair mate attraction going on between Dad and the bird on the branch, creating an interesting mixture of aggressive and compatibility behaviors (soft vocalizing=compatibility, while threat-bout=aggressiveness). While it had never occurred to me that the two eagles might be familiar to one another, Brett also pointed out the possible familiarity of the intruder with the incubating adult. A quick search of documented nest intrusions makes it obvious that this is far from a full-metal response. Here are three aggressive reactions for comparison. Bob was quite fascinated by the second one:

• Night-time raccoon intruder (note very direct response and gaze!):
  https://youtu.be/RWJfTaO-Wz0. 
• Hawk attacks bald eagle on eggs (hawk does not survive - response and gaze are direct!):
  https://youtu.be/2s8anVG-o_I
• Bald eagle attacks owl for trying to take over nest (owl survives and is chased off):
  https://youtu.be/B0eaDz1noRg

Jim went on to provide an alternative interpretation of the interaction.

"An alternative interpretation might be that there is a conflict between opposing behaviors, such as aggression toward the intruder in conflict with, or inhibited by, a higher drive that results in priority on protecting the egg (against either the outsider or accidental damage by the parent itself if it were to move around too much near the egg, as in the behavior of balling of the feet when moving around the egg). All of this is stereotyped action patterning that has been shaped by eons of evolution. The interactions have likely happened many times ancestrally with selection of survival and reproduction producing the optimal solution of trade-offs.

Contributing to all of this is the fact that the perched outsider, younger bird, isn't making moves toward the incubating adult and also not staring at it, but just mostly looking away ... as if they're familiar with each other, or that any serious interaction occurred earlier and have now run their course so we're just seeing the end of it.

All in all, it somewhat reminds of the reduced level (to my Ontario and previous MN experience) of aggressive interactions that I observed among close nests when we were doing the FWS aerial monitoring surveys along the Mississippi River in 2009. We might be seeing a new social order in eagles! (Or, at least new to us, behaviors that are more likely elicited in a new [to us] high-density eagle population [and high productivity of prey base, so food shortage is not a factor].)"

In short, what looked to our eyes like an aggressive interaction was not really very aggressive. Dad didn't challenge the intruder with a direct gaze, loud vocalizations, or an attack. He might be familiar with her (and possibly even attracted to her), or an aggressive response might have been inhibited by a higher priority to protect the egg. The intruder also wasn't aggressive. While she remained near the nest, she didn't try to enter it or engage Dad directly, and Mom displaced but didn't seriously attack her when Mom arrived at the nest. While we think of bald eagles as being non-social on their breeding territories, their interactions with and signaling towards visitors and 'neighbors' may be more complex than we initially thought, especially as the population becomes more dense and interactions become more common.

Many thanks to Jim and Brett for sharing their experience, wisdom, and insight!

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I became curious about eagle-to-eagle interactions after reading Jim and Brett's comments. A few videos:

• Sub-adult chased off by juvenile. This is an aggressive interaction, although no physical contact occurs. Note the loud vocalizing and direct attack: https://youtu.be/vnu0ZEJEAJw
• Adult to sub-adult interaction. Another aggressive interaction. Note that eagle on the nest doesn't stand up to defend until physical contact is imminent, perhaps lending support for Jim's idea that aggressive responses might be inhibited by a higher priority to protect eggs.
  https://youtu.be/9VdEmxLgPGo
• Adult to sub-adult interaction. This is interesting and not especially aggressive, although it includes physical contact. The adult (the video identifies it as male Romeo) is watching something outside the nest. At 3:34, a sub-adult eagle lands in the nest. Romeo flaps at it, but it looks down and away without responding directly to him. For the most part, the two eagles avoid direct eye contact. At 5:31, the sub-adult appears to check out the adults talons. The sub-adult nips at the adult at 5:34 and the adult flies off. https://youtu.be/_7BssmkllQY

We are sure people are curious about whether or not the intruder could be offspring from a previous year. We can't dismiss it, since eagles are philopatric, but we also can't confirm it. Perhaps further research will shed light on the relationships between bald eagles and sub-adult offspring.