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The Lesser Kestrels - a new and significant addition to the Soysambu Raptor Centre

The Lesser Kestrel (Falco naumanni), is a diminutive falcon weighing only 90-200 grams. It belongs to a cosmopolitan group of reddish-backed, hovering falcons with a short middle toe that catch mostly insects and small rodents and lizards. The larger kestrels can hunt small birds such as our Greater Kestrel and less frequently the Common Kestrels. Their names are not overly imaginative giving rise to Lesser, Greater, Common, Rock, Mountain, and when scattered on islands they are simply prefixed with the island name: Mauritius, Seychelles, Madagascar, Moluccan, Australia, etc. The one with the best name is undoubtedly the Fox Kestrel, a long-tailed brick-red Sahel wanderer. The Grey, Dickinson’s and its close relation the Madagascar Barred Kestrel are not kestrels in shape, biology or behaviour and it is only for want of a better word that they are erroneously called “kestrels”.


Only the Seychelles Kestrel is smaller than the Lesser Kestrel, although the not closely related American Kestrel can also be smaller. The American Kestrel and the African Pygmy Falcon are behaviourally very similar and if viewed with a squint, somewhat alike in build and plumage and disposition. They are both as hard as nails, pugnacious and very predacious despite being tiny.


There is an odd pronounced sexual size dimorphism in Lesser Kestrels that Tom Cade pondered over in one of his books, The Falcons of the World (1982). The male is some 76% the weight of the female. This alone should prick the ears of raptor buffs as it would imply a bird hunting diet. It’s the rule in merlins and falcons in general as well as most accipiters. He prompts that “it would be interesting for someone to record the difference in frequency and characteristics of hovering in males and females; females (prediction based on wing loading) should hover less, and flap more during hovering than males”. Over the years I have watched thousands of these kestrels and I can’t see any difference in performance. Perhaps because we see them in their wintering grounds or on passage from either their Eurasian nesting grounds or from southern Africa, they weigh, and thus fly much the same? I suspect it’s to do with the rate the sexes put on fat and the need for fat reserves to be immediately deployed to make eggs when they arrive at their breeding grounds.


Left: Adult male Lesser Kestrel by Laila Bahaa el Din (NB pale talons) and adult female Lesser Kestrel on the right.


Its status is peculiar because at one time it was listed as Threatened by the IUCN during the 1990s. There had been massive die offs due to the poisons in Israel (Thallium Sulphate rodenticide) and in West Africa (due to Red Billed Quelea Spraying). As a result, when we first opened up research opportunities in 1990 everyone wanted to study them. I recall once having to go to the National Museums in Nairobi to interview potential students; keen young things eager to save raptors. On the way there I went to the Sarit Centre, a huge shopping Mall with a very liberal use of space for the car park. It was raining and the sky was filled with some 7,000 Lesser Kestrels and hundreds of Amur Falcons. Right over the car park in the middle of a city! They were eating flying ants that seemingly erupted from every crack in the pavement. When I got to the Museums only a few kilometres away (still with falcons overhead) to interview the nervous students, each came up and said they wanted to study Lesser Kestrels. “Why?” I asked. “Because they are rare and Threatened!” “Have you ever seen one?” I asked. ”No”, they each replied, illustrating how study choices can be led by potential funding and how expectations of rarity can be influenced by IUCN status. In those days not a single African raptor was listed as endangered and back then Lesser Kestrels outnumbered our own Mountain Kestrel by 1000s to one. At some point they were down-listed (rather sheepfacedly) to “Least Concern” and then for some reason no one wanted to study them. Four decades on, there is every reason to be concerned if our much lower wintering numbers are an indication. In South Africa former roosts are defunct, here instead of tens of thousands only a few thousand. They should be up-listed.


As a rehabber we are often one of the first to know what risks are posed to raptors in the wild. It’s not a statistic to us, a tick on an excel spreadsheet. It’s an unfolding tragedy that is accompanied by immense stress and months of work. It is during these highly charged times, that solutions to the factors that led to the raptor being harmed, obsesses the mind. This watchdog role we play alerted us to the loss of raptors due to poisoning, either by Quelea spraying or the poisoning of large carnivores. The motivation to resolve these negative factors becomes personal, whereas to a professional biologist it need not be.

Now that electrocution accounts for the highest single cause of intakes into rehab we should be excused for concluding it to be a very serious threat. As a result we are increasing the level of our vigilance in the field and trying desperately to reopen this issue which we first raised nearly 30 years ago. In response to this, in conjunction with The Peregrine Fund and Soysambu Conservancy we have conducted “below power line” carcass counts. It’s a rotten job, and one fraught with opposing variables that makes any conclusion with regard to real numbers being killed impossible. For example, a dead raptor doesn’t last long on the ground. It gets eaten by hyena, jackal, mongoose, genets, dogs, cats, goats, other raptors and picked up and removed by the curious human. From death to being taken away, can be as little as 15 seconds as was the case of a Pied Crow I saw get electrocuted near Gigil. Very few carcasses remain overnight, and we just don’t have the time and funds to do long transects a number of times a day. Besides, we don’t have that many living raptors to electrocute these days. With an estimated 10% of the population left to kill, our statistical analysis of the problem is shot to pieces at the outset. “Below power line" carcass counts, although appropriate in other parts of the world, are misleading of the real numbers killed here. It’s indicative, but not representative.


Stephen Githenya joined us in January 2024 to help get an idea of the scale of the problem and how to mitigate against it on Soysambu Conservancy. It was during one of his monitoring forays that he found three Lesser Kestrels under one pole. Two were alive, the other dead. The pole differed not at all from the hundreds of others. And there were thousands of kestrels taking advantage of the recent rains and magnificent perches provided to them by the power poles.


In the foreground are three electrocuted Lesser Kestrels, two of which are still alive.

In the foreground are three electrocuted Lesser Kestrels, two of which are still alive. Two poles down is another kestrel and 5 poles down three others showing how favourable power poles are for perching raptors. (Photo: Stephen Githenya)


Stephen had found a number of other electrocuted raptors, for e.g. three Tawny Eagles on a section that had “taken out” my breeding Tawny a few years previously. The attrition rate of Tawny Eagles in that one territory in two months was (depending upon how you view it), 18 times greater than the pair could sustain over the period of one year! There is nothing unique about these 33 KVA cement poles, there’s tens of thousands of them all through our protected areas; all of them “open for business” of a similar nature.


The two Kestrels were returned to our centre, with only the very smallest signs of injury. We had seen this all too often and made the prediction that one wing and one leg of one and both the wing tips of the other would die and be amputated. When discovered they had only just been electrocuted as they hadn’t hopped away into thicker cover and were exposed to immediate predation by eagles sitting on the taller transmission lines above. Had Stephen and Kyalo been one hour later they would have seen nothing and thus would have concluded “no mortalities”.


Rescued Lesser Kestrel adult female with small burn on distal tip of the wing.

Rescued Lesser Kestrel adult female with small burn on distal tip of the wing. This and the other wing made contact and resulted in the wings dying to the radius and ulna and to the humerus. (Photo: Stephen Githenya)


One was more lightly coloured and streaked than the other and smaller. Perhaps a juvenile male? We will have to wait and see. Kestrels have successfully bred in boxes this size and that would be a wonderful thing to turn a tragedy into a success story. Some may ask if the captive bred young would not be able to know in which direction to go “home”, but they will follow the crowd and end up figuring it out.


One by one each limb dried, turned black and fell off. No surgical intervention is necessary or advisable. Once the skin is burnt there is no regeneration over the bone that as a consequence is often exposed. Along with nerves, vessels, tendons and muscles the area where the live contacts are “shocked” dies. It’s important to ensure flies and their maggots do not get at it, and that can be difficult as it goes rotten quickly. We used to amputate the bone just proximal to the margin where it is dead, but this would remove a tiny fraction of living bone that would often be valuable. Every millimetre counts when it comes to the use of the amputated limb later in life. Most of the time the limb goes black and dries and is still used, then it snaps and drops off, leaving a minimal wound that soon heals over.


Naturally all of us at the centre considered euthanasia. Part of me these days struggles to use the economic sensible consideration; this being that the birds cost money and time. We could use their enclosures, food and time on others that are likely to live and be released. Rehab is the return of wild animals back into the wild, and in some countries if you cannot guarantee that then one is dishonest to that interpretation. Frankly I am too exhausted to think beyond the need to live, whether in the wild or not. The wild isn't such a cool place either…that’s why we are working so hard to try to protect it, even in protected areas. Our captives here played a pivotal role at national level for half a century and finally these are the only captive kestrels of any kind to be seen by Kenyans anywhere north of the Zambezi and south of the Sahara. On that note our small crew of Mzee Mwanzia, his son Kyalo and Stephen and mzee me were determined that they should live. And we would make the best of it for them.


They spent a month convalescing in a small box and were nursed back to health. The one legged kestrel somehow got about fine and became tame very quickly. The older female with two missing wingtips was not so happy. Their first ICU box was a bit small and miserable despite it being placed above head height so that they could look down upon us. So, over a long weekend I set about making a new elongated box/diorama. I am very keen on dioramas, the kind of thing you see stuffed exhibits in museums where they paint in Kilimanjaro and put in fake trees. I had long had this vision that one could make all our raptor enclosure look like the real thing. Big zoos make massive cliffs and water themes for chimpanzees, Polar bears and lions and I see no reason why one can’t do the same for a raptor. If the raptor cannot be released, having for example a blind eye or missing wing, then a small natural looking environment is going to be a heck of a lot nicer than a hideous (but spotlessly clean) square concrete box. Dioramas can be vastly educational too. Fill in the background with the kind of habitat you’d expect to see the raptor. Put in plants that fit into that habitat too. Glue a delicate (but plastic) butterfly that occurs in the exact habitat near to the viewing window. Hang weaver bird nests, make moss and lichen (out of grated soap or papier mâché), leave a shed snake skin on the floor, etc. Go the extra mile and put in fake lion pug marks around the water pond and your guests are going to take a double look and freak out. Meanwhile lurking in the shadows are a pair of living but unreleasable raptors that are happily going about their own business, even breeding. How can one get more educational than that?


I bought at an outrageous price a foam insulating aerosol can and dug about in the rubbish for some polystyrene packing boxes. Putting them together and spraying the foam and using a hot knife heated over a stove I cut out a tiny cliff, with two small “caves”. Enjoying myself I set about painting them and then the backgrounds, just like those museum dioramas. But in miniature. I even put in a few aloes on the cliffs behind and finished it off with a distant lesser kestrel perched on the cliff behind. As to make the display educational I added a dark note. Realism if you like. I added a long stretch of lethal power lines stretching from the mid distance to the far distance.


The diorama box with two cliff faces and two nesting boxes.

The diorama box with two cliff faces and two nesting boxes. If you look carefully you can see the tiny image of a male kestrel sitting on the left in the “distance”, and the ominous power lines beneath.


When it was done we put the kestrels inside. They were initially frightened about the amount of light and exposure to the sun at first. Kestrels are very shy. The one legged tame one settled in quickly, found a “cave” and dived in head first to reappear looking out the hole. The other, though much more able to get about, took longer. They are high up and they look down on us like the “King of the Castle''. One by one they emerged to sun themselves and to even stand in the rain and take a long needed bath.


The kestrels enjoying a sunbath outside their “cliff” nest.

The kestrels enjoying a sunbath outside their “cliff” nest.


That evening as it got dark a strong solar powered light came on automatically in their box. I had taken the extra mile, one mile further. I’d figured that their brethren winged their way back north to scatter themselves from Spain across Europe into the Far Eastern Steppes where the sun stayed up until 10pm, that I should add 3 hours of extra sunlight. That way, hopefully, they’d feel that they had flown back.


There’s a strong message in that box, and one that should hang on the conscience of all of those who don’t think things through, do not adopt international standards, do not halt the unnecessary use of unsafe lethal power lines through protected areas or in areas of high bird densities. Yes, we need electricity to develop our economy, of that there is no question. But we should adopt best practices such as that used elsewhere. Not a single bird or animal needs to get electrocuted if the right structures are put in place. And when we achieve that, we get a more reliable power supply. It’s a win win.


 

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The box is awesome! and the light, too! thank you a thousand times😍

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