If you have been following the website over the winter you will know that, following his move to the Ivory Coast in December, AW generally remained faithful to a short six-mile stretch of river in the central part of the country. Then, in early February, he began to spend an increasing amount of time 20 miles away on the northern most reaches of the vast Lac de Buyo. He was spending most days at the lake and then returning to the river each evening to roost. There was nothing in his behaviour to suggest anything was wrong, but worryingly, we have stopped receiving any data from his transmitter.
The last GPS transmissions we received were on 17th February (the last ones shown on our Google Earth pages). The last three positions – for 6am, 7am and 8am that morning – all give exactly the same location: 6.78450,- 7.00117. That in itself was not particularly worrying; as we know from our recent trips to West Africa, wintering birds often spend prolonged periods on the same perch. What is far more concerning though, is that the only data we have received from the transmitter since then, are six non-GPS positions received 24 hours later on 18th February which suggested that AW was still in exactly the same spot. This was confirmed by the transmitter’s activity meter, which also showed that he (or the transmitter) wasn’t moving.
So what has happened? It seems there are two possibilities. The first is that the transmitter has fallen off. The transmitters are held in place with a teflon harness secured with cotton. They are designed to remain in place for five years or more, but when 06(01) returned to breed at Rutland Water in 2003, her transmitter had fallen off; and the last data we had received suggested she had gone down in the North Sea. So there is a chance that the same thing has happened to AW’s transmitter. Perhaps it has fallen off and is lying upside down, depleting the battery? The other possibility is that AW has come to grief somehow. Unfortunately the satellite imagery for this part of the Ivory Coast is very poor but the last positions we received are from what appear to be an area of cleared ground; not the sort of spot you would expect an Osprey to roost in, and certainly not somewhere they are likely to linger for 24 hours. The satellite data shows that on the evening of 16th February AW had been perched – perhaps on a dead tree in shallow water – a few hundred metres out from the shore. It is likely that many of the locals living around the lake are fishermen, and so perhaps AW became tangled in a discarded net? There is also a chance that he was intentionally killed. Living on the Edge: Wetlands and Birds in a Changing Sahel, a fantastic book that highlights the conservation issues facing birds in sub-Saharan Arfica, suggests that persecution is far more of a problem inland, than on the coast. In inland areas people tend to be concentrated around lakes and birds inhabiting these sites are, therefore, more likely to be intentionally taken. We have experience of this with our Rutland Water Ospreys – in 1998, 04(97) was killed by a farmer in Guinea, who only realised the significance of the bird when he noticed the rings on its leg. Once he realised the bird was ‘on a mission’ he took it to the British Embassay in the capital, Conakry. If a similar fate has befallen AW, then it emphasises why our education work in West Africa is so important. I know from various conversations in Gambia and Senegal, that people are less likely to kill birds if they understand more about the incredible journeys that Ospreys and other migratory species make each winter. We know that AW flew almost 4000 miles from Rutland Water to the Ivory Coast. It would be a desperate shame if he has now come to grief at the hands of humans, especially as we tagged him because of the problems we have encountered in Rutland in recent years.
We have been checking the data regularly, in the hope that the radio would suddenly spark back into life, but with almost a month having now passed, that seems very unlikely. We will just have to hope that AW returns, minus his transmitter in a few weeks’ time. Thankfully, 09 seems settled on the Senegal coast, and so, at the very least, we should be able to follow his return journey north over the next few weeks.