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Understanding the potential of mortalities and a case study of an electrocuted Marital Eagle


We have attended enough workshops on bird electrocution to recognise that not everyone, including those who work in the distribution of power, understand how electricity can kill a bird. Often patiently explaining to us that birds can perch on power lines with complete immunity. In my previous blog I mentioned the slow death of Boy the Martial Eagle, but I did not properly expand on how electric shock often kills these large birds slowly. And I didn’t emphasise the implication this has on greatly amplifying the extinction risk posed by power transmission that can never be accurately enumerated by conventional means.


It is vitally important to repeat clearly the processes that lead to mortality so that researchers, authority and the public understand that there is more to it than the blatantly obvious method of counting ‘dead birds under power pole’ statistics. In this blog I go into more depth of yet another tragic repeat scenario, this time a juvenile female Martial Eagle, also electrocuted in the heart of a protected area by these newly installed lethal structures which have no provisions at all to make them safe, despite decades of asking for change.


Insights from the frontline

To us at Kenya Bird of Prey Trust it was a double tragedy because had both “Boy” and the new female survived, they would have made a suitable breeding pair. Martial Eagles are relatively easy to breed in captivity. But would it, under the current circumstance of continued expansion of lethal power lines, be responsible in letting their young go? No, not until those power lines are made safe. So raptor rehab that does in time lead to captive breeding must lead in halting those losses that occur in the wild and that led to the bird being brought in for rehab in the first place. It’s this circle that defines our multiple, if overwhelming, objectives of the Trust. We are not “just” a rehab organisation but in doing rehab we are often placed on the frontline. By virtue of comparing the reasons for admission we are well placed to identify potential reasons for overall population declines. We really would not have known the danger of electrocution had we not been working in raptor rehabilitation.


Remove factors that lead to declines

So first things first. Those very obligations that the IUCN and Species Survival Specialist groups advise, need to be cleared away before the prodigy of captive bred Martial Eagles are freed. “Get rid of those factors that led to the decline of the species first”, we are told by these organisations. Most pragmatic conservationists disagree with the “first things first principle” and after identifying the problem see it as wasting time, finance and resource not to launch both the reconstructive restoration project in synchrony with the removal of the factors that led to the species’ demise. It’s logical, time saving, financially less costly, and logistically easier to launch symbiotic projects together and it applies pressure and urgency to removing those factors while everything is fresh in the minds of the public.


It’s a tall order to remove those “bad” problems, especially when we have additional protocols, permissions and restrictions and extra costs today that in yesteryear were absent. In addition, we are increasingly asked to ensure community buy-in at mega scale, guarantee climate change reversal, increase standards of living, when we actually have skill sets that can do only one part well. The mega-scale matters are the mandates of mega-organisations and government institutions and we (and potential supporters and funders) must recognise our role. We can supply them with the facts and the logic that can provide them with much of what is required by funders of development projects.


We are not proposing a return to how things were. We accept that there have been entire countrywide changes that will never return raptors and wildlife to their previous numbers. But in this new landscape we do propose getting many raptor species back to healthy sustainable numbers. Given a little help, raptors have the ability to exist in man-made landscapes. They have been for tens of thousands of years, but the urban metropolis raptor is a recent thing that offers new hope to augmentation projects. The most contemporary conservation actions today, especially raptor conservation, accept that we cannot get things back to pristine normal. Carl Jones, one of the most successful individuals in bird conservation, is a convincing advocate for putting things back in human altered habitats and that’s what we plan to do too. There is not any other option left. But, we had better fix those deadly power poles while we set about restoring the species and working with the wildlife authorities and local communities to empower them to do it.


The hard facts of death by electrocution

Before describing how an electrocuted eagle literally falls to pieces despite every effort, I spoke to my colleagues to ask if they thought the average raptor enthusiast would be put off by the harsh reality laid out in a clinical manner that could perhaps also serve as a reference document for veterinarians, raptor conservationists and those planning transmission of power. The unanimous answer was ”they may be but you have got to tell it how it is!”. They especially asked for a detailed account of how bits, thin distal parts of the bird’s body, instantly die, yet remain physically functional enough for them to exit the “scene of the crime” to die later and thus be overlooked in conventional appraisals of the mortality caused by “electric shock or electrocution”.


The reason it’s so important to know how and why birds die after a sub-lethal “shock” is that statistically the numerical abundance of the new lethal designed concrete poles may be sufficient to alone cause the loss of entire species even in the core of our largest protected areas. It may or may not be, but common sense does strongly hint that this is possible, and so science has to step in and take over to prove or disprove it. One thing it cannot do is say that electrocution is not a contributory factor to already precipitous declines because that would defy logic. Contributory factors have a habit of adding up greater than the sum of the total expected. This synergistic relationship where two or more factors do not add up to an expected sum (in this case mortality loss of raptors) but greatly exceed it, is not a new biology principle and it is relevant in this discussion.


Understanding the potential of mortalities and making estimates based on this potential

Imagine placing 10 gin traps on high poles on a pheasant rearing enclosure in the core territory of a pair of European Goshawks. Given what we know of goshawk prey preference, their perching behaviour, inability of prey to seek cover and the effectiveness of the gin traps, would it really be worth the while of a scientist to study the outcome? Or could they just conclude, without wasting time and money, that the goshawk pair will soon be extirpated? The game keeper who set the traps would certainly know the outcome without having to visit the site, so why not the scientist?


Imagine others setting ten thousand self setting gin traps through a thousand raptor territories and having to get the permissions and budget to study the outcome when there are not the resources to do the study? Do we conclude that there is insufficient evidence to suggest catastrophic loss? Can we refer to similar studies made elsewhere in the world and use these as evidence of threat to our population? Would we be justified in suggesting that fundamental laws that ban the killing of endangered species should apply to known causes of mortality? Apparently not, for we have been asked to provide local evidence in a local setting as this would be more accurate. In other words, a post construction study which ridicules the fundamentals of science based, pre-construction, environmental impact assessments.


To understand the magnitude of the problem it requires thought theory to conclude this for we do not have the financial resources, permissions or time to get the hundreds to thousands of empirically recorded deaths deemed necessary to prove rates of declines in each species. We don’t have accurate population numbers of species either, and cannot know adequately for the same reasons, leaving us with a statistical impossibility of enumerating a population in rapid decline.


The shifting baseline

With each generation of “study” we experience a typical but harmful bias and this is termed the “shifting baseline”. The baseline is in theory the original pristine number counted before a decline and then all changes are charted during a study on a graph and we get a neat curve that everyone understands. We depend largely on student studies done by individuals with no prior history in the subject to deliver these data and make conclusions (most graduate student studies are 9 to 24 months). They enter the project under the assumption their first count is the pristine true number and there lies the problem. They may even be denied by their supervisors to refer to publications made 10 years previously, making a mockery of previous baselines obviously much closer to the true holding capacity.


It's tough making an analogy but a friend of mine, Craig Sorely, has put it quite well. It’s a bit crude but here it goes.


We task a research team with studying the health of 5 crash test dummies in a vehicle accelerating from 200kph to 300kph. Every 100m down the track we place a neophyte PhD student with a clipboard. Every 300m we give them new supervisors. As the car whizzes past them at 1/1000th of a second, each student calls out that the “study group” is doing fine. Let’s freeze time for a few years. The collected data is studied and pondered upon by think-tanks unaware of the consequences of the trajectory because of their lack of longevity and experience in the particular subject, and they rightly conclude that all is well. They haven’t any need for a contingency plan, they haven’t put in brakes, or safety belts or airbags. The method used in this study is flawless, the data acquired empirical and unchallengeable: the dummies are fine.


At the end of the track is a brick wall. To make the analogy better to equate is that we don’t really know where that brick wall is. The analogy would be even better if we had tinted the windows and didn't know how many passengers there were in the car either. But the brick wall is there.Now imagine the last student positioned 100m away from that brick wall. This student's anguish is not supported by the previous students or their supervisors or the previous scientific reports. That student will have an overriding sense, governed by logic, that overshadows the science but is inadequately prepared to articulate it for common sense, intuition, logic and emotion are not acceptable in science.


Those that have done many crash tests know the outcome is pretty serious, so it’s those with prior experience in the same discipline that are best suited for the project. They are the ones that make good brakes, safety belts, air bags, roll cages and post accident rescue services. Importantly they didn’t use real people, or real roads in these tests either, they used experiments that replicated the situation. In the raptor electrocution business we too have, and can continue to do the same.


If modern scientific convention is allowed its way, a measurable decline in the subject species MUST BE PROVED to have occurred by the offending development and by no other cause, if any mitigation is to be made obligatory. Ironically this modern scientific convention is increasingly paid for by developers as part of their mitigation obligations or foundations that must include “sustainable development” as a prerequisite bias. Scientific proof of today needs to stand up in court and face thorough cross examination by those prosecuting the offending party (the developers). Speculation and anything nearing an emotional appeal is not just dismissed, it is taken as evidence for corrupting science. The case must be watertight and this plays to delay we cannot afford. This works in favour of the developers of course. E=mc2 would be unacceptable to them despite it being a theory that results in a fact.


Thought theory requires no permit, no extra-costs, just logic, strong coffee and a couch. But first it needs the knowledge of some of the variables and here we focus on how mortalities can be overlooked and grossly under-represented by closely examining the effects of non-lethal electric shocks.



Case study Martial Eagle, Tsavo West

Here is a repeat scenario, but this time with a juvenile female Martial Eagle, also electrocuted (shocked) in a protected area by these newly designed lethal structures which have no provisions at all to make them safe.


On 17 Feb 2022 a rapid chain of events happened when a Dutch couple posted pictures and videos on social media of a young Martial Eagle flopping around in front of Salt Lick Lodge Taita Hills. Thousands of miles away in the Netherlands it was seen on Facebook by Britt, who told Stratton Hatfield (Africa’s foremost Martial Eagle biologist) sitting next to her, who immediately informed the rest of the KBoPT team and that sent Nick Trent scrambling to get it. We knew what had happened and time wasted would see that eagle killed during the night. At the lodge, rangers, KWS staff, tourists and tour drivers were all informed and all converged to save its life before the night fell. You couldn’t have had a more involved chain of events and all thanks to “live” social media reporting spanning the world in real time.



8 Feb 2022 - Day 2 - Post electric shock A captured video frame showing the Martial trying to fly. In the background is an electricity pole and to the right is the lodge which it serves. The guest and guide can be heard noting that the eagle needed to put a lot more effort into flying, little realising the ominous meaning of that pole.

To us it was all too evident that the eagle had been electrocuted and would die unless rescued and its chances of a recovery on its own were zero. Martial Eagles are Endangered, and thus effort made to rescue one is obligated upon us all. The lodge rangers picked her up and kept her safe that night…an act that needs recognition as today so few citizens act on impulse to save Endangered species. It takes courage these days to act.


9 Feb 2022 - Day 3

Below the lodge rangers just after rescuing the eagle and a photo they took at the time. The wound looks deep and the tendons are exposed. At that temperature maggots had already begun their work and the eagle is most probably trying to tear them out resulting in trauma around the site that can obscure the burnt feathers, skin and flesh.

Nick arranged the rescue with KWS and the lodge and sanctuary staff met him the next morning and the Martial Eagle was duly delivered to Soysambu where her status was immediately elevated to “critical” and she was given fluids, food, warm enclosure and immediate removal of hundreds of fast growing maggots. She had self-mutilated overnight, as did Boy and as do most raptors when trying to remove maggots from their wounds. This rendered all chances of her recovering flight impossible. Her opposing foot, deceptively still working and looking good but for a few burns would, as experience has shown us, die. How much we didn’t know.


10 Feb 2022 - Day 4

After the first clean and removal of dead flesh and maggots the radius and ulna are clearly seen as are the major tendons, vessels and nerves that attach to the carpus. Note the rapid change from day 2 to day 3 due to facultative myiasis (maggots eating dead and opportunistically eating living flesh). In this case two effective methods were used to kill and remove the maggots, firstly was the use of Healing Oil (Coopers) easily found in any small town agri-vet. The second was WD40, a fine oil commonly used in mechanics but perfect for killing maggots as well as blasting them out of pockets with minimal damage to living tissue. Some tendons, vessels and nerves can be clearly seen to be bitten and cut by the eagle’s bill in its attempt to remove the maggots. The bird was still able to open and “use” its wing in this condition.


11 Feb. 2022 - Day 5

On first examination of the foot, only the obvious surface burns and lesions can be seen. The middle toe burnt through to the tendon beneath, the hallux and inside toe are burnt mid section, and the outside toe is changing colour. It would have been easy to overlook had no one known the “double tap” that electrocution typically delivers. One on the distal wing underside, one on the opposing foot.

It is not possible to determine if these toes are alive and supplied with blood and nerves. Lancing with a needle to determine pain or blood presence is inadvisable when it is crucially important to be as non-intrusive as possible with already damaged tissue that is given to infection.


We were fortunate to have National Geographic Magazine photographers staying at the centre and they had a thermal scope and by using this we were able to see that the left foot was almost entirely cold, dead in other words. All the toes of the left foot were not supplied by blood and technically dead, though still operational. The eagle was even standing on its dead foot for weeks afterwards. This forcefully illustrates the ability to grossly underestimate electrocution related deaths of raptors because the dead feet can take a very long time to become non functional.


How can a dead foot work you may ask? The muscles that open and close the foot, and the primaries of the wing lie in bundles near the core of the body. Hopefully there are very few of us who have not played with the severed foot of a chicken and pulled the tendons to see the foot open and close. This severed foot has no muscles, very little water and very little physical bulk and so it is physically unable to pass a huge amount of electricity. When it does it burns and dries in a flash thus acting as a circuit breaker leaving the large muscle mass that operates it less harmed.

The black and white thermal image taken of the limbs shows blood flow indicated as heat (white). The right foot of the eagle is white showing heat, while the toes of the left foot do not. Note the eagle is standing squarely on both feet despite one being dead. The right wing shows the absence of blood supply in the dark area, but surprisingly shows the potential for still living tissue over the distal radius and carpal joint. Here I overlooked the potential for the patagial vein to supply blood to the distal part of the radius and ulna. It later transpired that the proximal part of the distal part of the humerus was in fact dead, though the proximal part of the radius and ulna was viable. An “island” of detached living tissue proximal from the body was not anticipated and it was here that profuse bleeding occurred under bandages.


To our knowledge the use of thermal images to identify conditions of this kind (and osteomyelitis) in raptors is novel. (Photos courtesy of Bobby Neptune and Stratton Hatfield).


22 Feb 2022 - Day 16

The eagle is standing on the dead foot. This led to us re-examining the good foot and noting it too was developing burn lesions on the pad. The “white” indicated in the thermal image could also be indicating infection and inflammation. The good foot could feel pain, the “bad” foot could not. Reinforcing the implication of raptors using a limb normally long after electrocution.


14 March 2022 - Day 36

After the wing dried it was amputated mid radius and ulna in an effort to keep as much of the wing as possible. The dried wing is shown on the right.

With other raptors we have found that it is better to wait until the necrotic area dries and delineates the exact position on the limb bone where amputation should take place. We have been able to preserve the longest possible limb length therefore and have had no need to guess and perhaps cut back too far. In addition tendons will form unions with skin or bone that allow the remaining limb to work near to normal.


This exposed bare bone can be used temporarily to support weight or provide balance. The flesh around the exposed bone is debrided frequently till clean and in 4 to 16 weeks the bone may break perfectly at the cuticle to bone union site. Only then is the bone cavity capped (some bones are air filled and must be capped) and surgically pushed under the skin in a five minute procedure. The limb is then given an external prosthesis and thought given to ITAP (Intraosseous Transcutaneous Amputation Prosthesis) use. In this case we planned for ITAPs in both radius and ulna that would provide excellent rotational strength, perhaps sufficient to mount a “wing” prosthesis that would provide more than just balance.


The eagle was still using its left foot although the toes were not opening and closing as well as before. The quality of life was good; the eagle was otherwise fit and rapidly becoming tame and even playful and very ready to protect her meal! If she kept the remainder of the wing and could stand on the foot she was still a good candidate for captive breeding. If the wing required amputation at mid tarsus and mid humerus she would not be a good candidate for captive breeding. Thus the conservative approach to minimise the extent of amputations.


16 March 2022 - Day 38

The base of the foot is swollen and the digits are dry and blackened. The foot has minimal movement but can still flex. This was the exact condition of an adult martial female we witnessed in Tsavo East near Sala that had to resort to predating Tawny Eagle chicks in the nest. (see photos in last paragraph)



17 March 2022 - Day 39

Colour-coded thermal proved very useful in delineating the precise boundary between living and dead tissue prior to amputation of digits. The white distal of the red was viable tissue. The grey was dead and drying fast creating infection that could not be managed by antibiotics any longer.


19 March 2022 - Day 40

Amputation of all 4 digits, being as conservative as possible. The tendons were affixed to skin, not bone. This allowed flexation but not at high torque. We held hope for the potential for 3 D printed human digit exo-prosthesis given that the bones are larger than human digits.


The picture below shows an extraordinary circumstance where living muscle and flesh are isolated from the brachial vein, artery and medial-ulnar nerve supply. This explains the “hot” still living tissue seen with the thermal camera, but we did not anticipate the ability of superficial blood supply from the patagial vein to keep this isolated segment alive. Copious haemorrhage from the brachial vein, hidden under gauze and bandage, ultimately led to copious blood loss and severe anaemia.


20 March 2022 - Day 41

The eagle is standing on the plaster/foam caste over the injured foot. She ate well from the hand while standing. She slept in a heated kennel. The bleeding on the wing had stopped and we opted to leave it rather than open up the site and ligature vessels.


Initially, a month previously we put her on both oral Ciprofloxacin (20mg/kg) for 7 days and latterly on IM/SC enrofloxacin (10mg/kg) as well as iron supplement (Ranferon) for anaemia. The antibiotic appeared to improve her condition in the first month but infection returned as the necrosis of the tissue continued into the second month.


On the morning of 22 March 2022, 43 Days after injury, she was found standing in her box but with blood loss from her wing that had soaked the towels beneath her. The blood was pale and anaemic. Some further blood loss occurred after she was allowed to stand in the sun but it ceased on its own. Clearly extremely depressed but still standing, we opted for minimal disturbance and stress….that would have resulted in further haemorrhage from a site on the wing we previously could not locate. We would address that later after she had some time to recover. She was now in a precarious condition, for the first time.


I was obliged to answer the phone, ironically on a discussion about electrocution, when she collapsed and died.


In retrospect

In dealing with electrocution cases we are often caught in a cycle I call the “Black Knight scenario” (to be explained in another blog on an electrocuted Augur Buzzard). One limb after another becomes non-viable and you really don’t know which or precisely where until it happens. As they lose one limb after another, they look you in the eye as fearlessly and as strong as when they were fully intact. They tame down in days, become as engaging as a dog, demonstrate interest, happiness and intelligence and creep into that area considerate off limits and unprofessional. Your heart.


Did she die in vain? She would have been an unknown statistic last seen outside a lodge by tourists who witnessed her antics, had we not been alerted by someone in the Netherlands who could read the situation correctly. Will there be any changes made as one after another endangered species needlessly dies? Had she survived, would anyone who saw her pitiful state have cared enough to tackle the imposing developers that do not listen and seek defence in a never ending requirement for better data quantity and quality? After 27+ years of informing, we see no change.


There will be a next time. And forever more until Kenya adopts birdsafe power poles as other countries such as Mongolia and South Africa have done, plans around protected areas and avoids areas where raptors and large birds are most numerous. There are safe options. There is no need for a single eagle to be electrocuted, and it is not a cost we have to bear to pay for “development”.

 

On the left is a female Martial Eagle part of a study group in the Mara Triangle as a chick. On the right after it had been electrocuted.


The left shows an adult female Martial Eagle predating a Tawny Eagle chick near Sala Tsavo East, July 2021. On the right the close up shows the typical signs on the left foot of electrocution. Incapacitated in the core of our largest protected area and certain to starve to death as the foot rots off, this Martial will probably account for a number of other eagle chicks in the nest before she dies.

 

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