So what is going on? Well, here is what we know from the current batch of data. At 10am on the morning of 17th December AW was perched on the beach in his usual area, probably eating a fish. An hour later he had moved eight kilometres inland. Bearing in mind how little he had moved around for the previous few months, this in itself was a notable change from the norm; but nothing compared to what happened next. At midday, he was 13 km to the east, heading south-east at 30kph. Perhaps he was seeing off another Osprey? That obviously wasn’t the case though because an hour later he was another 27km further on and still maintaining the same course. This was more like migration! And that’s what he continued to do for the rest of the afternoon. By 5pm he was close to Conakry, the capital of Guinea having flown another 160km at a remarkably consistent speed along the coast. At 6pm he was perched either on the ground or in mangroves beside what on Google Earth looks to be a complex river delta system just to the south of Conakry. He was probably eating a fish; and no doubt there were plenty of other Ospreys around. He then roosted in mangroves 4km further south.
By 7am next morning AW was another 22km south-east, again perched among mangroves beside a river. He was still there an hour later but he must have resumed his journey soon afterwards. Although we are missing a series of data points, by 6pm he had flown another 180km south-east, and was resting close to a river in central Sierra Leone! Sadly the satellite imagery for this part of Africa is poor, but he appeared to roost in an area of scattered vegetation a couple of kilometres to the south. What was interesting was that he was now over 100km inland. Since leaving his regular spot on the coast the previous morning, he had maintained an incredibly direct south-easterly heading. It appeared that he knew exactly where he was going.
Next morning AW left his roost just after 9am and flew purposefully south-east for the rest of the day at altitudes of between 500 and 1200 metres. He crossed into Liberia in mid-afternoon and by 6pm, when he finally settled down to roost for the night, he had covered 280km. During his last two hours of flight he had changed his course to a more easterly heading. Whether this was an intentional change of direction or influenced by the weather, we are not sure, but we do know that he roosted close to the town of Basanai in northern Liberia. Again the satellite coverage of this part of Africa is very poor, but it looks to be a fairly densely forested area at an altitude of around 350metres. It is certainly not the kind of place you would expect an experienced adult Osprey to hang around so the chances are that AW will have continued his journey the next morning. His radio is currently on a five day duty cycle meaning we probably won’t receive any more data until Christmas Day. It will be absolutely fascinating to see where he is by then. Aside from his slight change of direction during the afternoon of the 20th, he had maintained a consistent south-easterly course for three days, suggesting he is heading for the Sierra Leone coast. Rest assured that we’ll update you as soon as the data comes in.
So what has prompted this sudden move? I rang Roy Dennis this afternoon and he was as stumped for an explanation as me. We have never recorded this kind of mid-winter movement by an adult Osprey before. It is possible, of course, that this is something that AW does every year. His southward migration was notable for a lack of stop-overs, but, in retrospect, perhaps that is all his time in Guinea was; an extended stop-over. Maybe his true wintering site lies elsewhere?
We haven’t yet updated Google Earth with this new data – but don’t worry, it will be done tomorrow morning.