Trapping Fish Eagles at Lake Naivasha
Munir Virani— 15 June 2009 — in East Africa Project    ShareTrapping African Fish Eagles is not only fun, it is incredibly therapeutic. Furthermore, it provides a wonderful opportunity to take photographs of these charismatic eagles in action as they majestically swoop down over the water towards a dead, belly-up floating fish. Sorry to burst your bubble but I am afraid that’s how all the “action” fish eagle shots are taken. The late Leslie Brown in his epic book “The African Fish Eagle” said that fish eagles spend on average only about eight minutes a day hunting. So it would be a long wait if you were to try and get the naturally perfect shot!!

Yesterday, I took my five-year-old son, Kaisaan down to Lake Naivasha in Kenya’s Great Rift Valley to trap and radio-tag some fish eagles. I always look forward to these ‘father-son” expeditions in the wild, more so because Kaisaan has reached an age where he asks lots of questions and is interested in taking pictures. I also love the fact that he can identify some of the common birds of prey. Kaisaan was up at 5:30 am and ready to go. We left an overcast Nairobi at 6:30 am and took the scenic drive down the Rift Valley where it was nice to see Augur Buzzards, Long-crested and Tawny Eagles perched on the side of the road.

We got to Elsamere Field Study Center at 8.15 am where we met Shiv Kapila, an MSc student who I am supervising from the University College of London (UK). Shiv is conducting a behavioral study of African Fish Eagles at Lake Naivasha and building on existing work that The Peregrine Fund has done along with the Earthwatch Institute and the University of Leicester. Birds of prey offer themselves as excellent indicators of ecosystem health because they are at the top of the food chain, occur in low densities and are good “flagships.” By having good numbers and diversity of birds of prey in an ecosystem, one is assured that they have plenty of good quality food occurring in the trophic levels below them. In other words, birds of prey are much like the avian equivalents of the big cats—the only difference being that birds of prey are far more exiting to watch (how many of you have boring pictures of sleeping lions?).

Since July 2008, I have radio-tagged five individuals that include two birds that I trapped with Shiv last month in good quality habitat along the western shores of Lake Naivasha. Shiv wanted to follow birds in marginal habitat and in areas where there was intensive human encroachment and lots of flower farms. Kaisaan, having slept all the way to Naivasha was in good form and really excited to trap eagles as he had done with me on previous occasions.

With the boat all ready to go, we headed towards the north swamp, near Loldia Farm where the habitat is more or less a fringe of papyrus belt with distant Acacia trees. I had trapped and banded fish eagles in this part of the lake in 1997 and those birds had disappeared. My hypothesis was that fish eagles might be dying at an alarming rate on the lake and because there is a large “floating” population of birds trying to take over vacant territories, the lake may be acting as a sink, which means it could be drawing in birds from outside Lake Naivasha that would subsequently die and get replaced again by other fish eagles before you could say “Bob’s your uncle.” That is why following marked birds over time can help answer important scientific questions. It is only unless one has a basic understanding of the ecological requirements of species, that scientifically sound conservation and management plans can be effectively developed and implemented.

The pair near Lentolia house proved difficult to trap and it never ceased to amaze me how fish eagles can be so individualistic and have so much character—just like humans. Some eagles are off their perch like a flash as soon as you start waving a fish at them, while others will take their time and weigh the situation before striking at the fish. And then there are those birds that will not come down to a floating fish at all.

We moved on to the Loldia male who was perched on a very low stump. Shiv had been baiting this bird for many days before and so as soon as we laid down the snared-fish, the eagle was off its perch. With sheer elegance, the fish eagle swooped towards the snared fish, thrust its feet forward and with lightening speed grabbed the fish. I knew we had this one! I felt a warm glow inside me as I heard Kaisaan say “we got this one Papa.” Indeed we did—a majestic male in resplendent plumage. As I pulled it out of the water, Shiv placed a hood on its head, which calmed the bird down and we began to “process” it. We carefully attached a solar-powered radio-transmitter very kindly donated by Ed Levine of Merlin Systems in Boise Idaho. As Shiv held the bird and I was placing a band on its leg, I could sense that Kaisaan’s patience was being pushed to the limit – “I am bored Paps,” he whined, “let’s go trap another one.” I guess the excitement of the trapping was over.

After taking weight of the bird and ensuring that the eagle’s wing movements were not impeded by the back-pack, I took some blood from the bird for Thecla Mutia, a Kenyan student also being supported by The Peregrine Fund to conduct a Master’s study looking at risk assessment of lead contamination on Lake Naivasha. Shiv finally released the bird, and much to our excitement and comfort, the eagle flew gracefully onto the same perch and let out its characteristic call—the call of Africa.

We tried trapping a few more birds near the horticultural areas but because the lake level has receded so much, it was difficult to get close to the shore and place the trap. So we called it a day, took some photographs and headed back to Nairobi. Kaisaan was fast asleep in the back as I pointed out an Augur Buzzard on the drive back. The day was far from over as I looked forward to an exciting World Cup T20 cricket match between South Africa and the West Indies that evening on telly.

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