Osprey AW

Male Osprey AW fledged from the Site B nest in 2006. He bred for the first time in 2010 at Site O (a nest on private land near Rutland Water) and again in 2011 with a Scottish female from Argyll. AW then spent several months wintering in Africa, but in February 2012 his transmitter stopped sending data. Subsequently he failed to return to Rutland for the 2012 breeding season.

Mystery solved!

On Thursday June 28th, John saw the young female who was the SIXTH Osprey from the class of 2010 to return to the UK. This female is the fourth two-year old to return to Rutland for the first time this year and John only saw a fleeting glimpse so he wasn’t sure whether she was 25(10) or 26(10). I’m thrilled to say that she paid a visit to the reserve today and we can now confirm that she is 25(10). She fledged from Site O in 2010 and is AW’s daughter. For more information about AW click here. She is likely to spend the summer exploring the area but hopefully in the next few years she will follow in the footsteps of her grandfather, ‘Mr Rutland’ 03(97), and return to raise chicks of her own.

25(10)

What has happened to AW?

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.

AW's last locations at Lac de Buyo in Ivory Coast

AW's last locations at Lac de Buyo in Ivory Coast

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.

When will the journey home begin?

How time flies! It is amazing to think that it is now less than a month before the first Ospreys will be back in Rutland. This year, for the first time, we’ll be able to follow our satellite-tagged birds as they head for home.

The latest satellite data shows that they are both still at their wintering sites; 09 on the coast of Senegal and AW in central Ivory Coast. In recent days AW has been spending an increasing amount of time on the shores of the vast Lac de Buyo, some 20 miles north-west of his usual haunts. Perhaps the fishing there has become easier, or maybe some of the other wintering Ospreys have already begun to move north, allowing AW to ‘move in’ on their patch?

AW's latest locations in the Ivory Coast

AW's latest locations in the Ivory Coast

09's latest positions in Senegal

09's latest positions in Senegal

09 meanwhile is still settled on the coast of Senegal, usually fishing less than a mile out to sea and then perching either on the beach or his favourite spots just inland.

So the question is, when will they start the journey north? Last year both birds returned to Rutland during the last week in March. Given that the flight north is likely to take them at least two-and-a-half to three weeks, we might expect them to begin their migration in early March. It will be especially interesting to see which way AW heads home. Will he fly north-west to his stop-over site in Guinea, or fly due north from the Ivory Coast through central Guinea and then into Mali? It goes without saying that we’ll be updating the website on a daily basis as soon as they start moving. So watch this space!

AW settled in the Ivory Coast

As we expected, the latest satellite data shows that AW has remained on a short section of the River Lobo in central-western Ivory Coast.

Over the past week he has ranged along a six mile stretch of the river and used three different roost sites, each a few miles apart. He is fishing in the river once or twice each day. Although the satellite imagery is poor, it is really interesting that the area he has now settled in is completely different to the spot on the Guinea coast where he spent over three months. He is now on the edge of a vast area of tropical forest known as the Western Guinean lowland forest which extends west into Liberia and south-eastern Guinea. From the satellite imagery it looks as if AW is in a slightly more open area more typical of the habitat that lies to the east. According to Wikipedia, the Guineana forest-savanna mosaic belt extends across the middle of the Ivory Coast and is the transition zone between the coastal forests and the interior savannas. One thing is for sure, it is very different from Rutland Water!

AW's roost sites beside the River Lobo

AW's roost sites beside the River Lobo

AW has Christmas in the Ivory Coast

I didn’t think I would be eagerly checking the satellite data on Christmas Day to find out where one of our birds has ended up, but that’s exactly what I’ve just done. Having spent the night of the 19th December in northern Liberia, AW has flown another 210 miles further east and is now in the central part of the Ivory Coast! For an adult Osprey to suddenly make this kind of move in the middle of winter is completey unprecedented, but it does suggest that the time he spent on the coast of Guinea was just an extended stop-over and that the Ivory Coast is his true wintering site.

So how did he get there? On the morning of 20th December AW began migrating again just before 10am. He continued flying for the rest of the day, maintaining a constant easterly heading at speeds of between 30 and 40kph at altitudes of between 500 and 1000 metres.  By 5pm he had covered 207km and was perched beside a river – probably eating a fish –  in the very western part of the Ivory Coast. He roosted in forest nearby. Next morning he was away again before 10am and again heading east-south-east. By 11am he had covered 36 kilometres and now changed to a more south-easterly course, heading towards the vast Lac de Buyo. By 1pm he was at the northern end of the lake and for the rest of the afternoon he zig-zagged the upper reaches of the lake, covering some 45 kilometres in the process. This was strange behaviour and suggests he may either have been interacting with other Ospreys, or simply unsure of where to go. He eventually settled to roost on the eatsern side of the lake, having covered 139km during the course of the day.

AW's movements around Lac de Buyo, 21st December

 

Next morning AW was back at the lake soon after first light, presumably fishing. He was at the lake for a couple of hours but by 10am he was migrating again, heading due east. An hour later he was perched beside the Lobo River river in a forested area some 20km to the east.  Interestingly, he then flew no further. Over the course of the next 48 hours AW made only local movements to various different points along the river. Sadly, the satellite imagery of this part of the Ivory Coast is poor, but AW’s behaviour suggests that there is plenty of food in the river. The fact he remained in the same area for two days suggests that this may well be his usual wintering site. If he hasn’t moved by the time the next batch of data comes in then we can probably assume that this is the case. He is now 975 kilometres from the spot on the Guinea coast where he spent over three months. This is a quite incredible movement and shows that just when you think you know everything there is to know about Ospreys on their wintering grounds, one does something competely new and unexpected.

AW's movements in central-east Ivory coast 22-24 December

 

AW's flight from Guinea to the Ivory Coast