Since last week’s worrying news of FR4’s disappearance we have all been waiting anxiously for any further information. Unfortunately none has been forthcoming – no new data has been received so it looks as if FR4’s tag has stopped transmitting. As to the reason for this it’s very difficult to say.
Although the last GPS data was for the 21st December, there was non-GPS data coming in up to 23rd December, which showed that FR4 was still in the same place.
We asked Roy Dennis for his expert opinion and he kindly provided the following analysis…
“There was GPS data missing on most days between 17th & 21st, indicating that the transmitter was not working perfectly, despite fact that the battery was fully charged and GPS readings should have been excellent in such an open area. The engineering file information suggests that FR4 was alive on 17th and 23rd but there was only a small difference in activity readings and these could be due to wind rocking a dead bird. So in summary, transmitter failure is a possible explanation but there is no definitive evidence as to whether FR4 is alive or dead.”
As many of you will be aware the team from Rutland Osprey Project are currently in Senegal and have spent several days exploring the Saloum Delta (Sine-Saloum). However the delta covers a vast area (73,000ha), most of which is inaccessible apart from by boat, making a search for FR4 very difficult in the limited time they were there. You can find out more about their West African adventure on the Rutland Osprey Project blog.
So not the news any of us wanted but sadly this is where we find ourselves. If FR4 is still alive and well then it is possible (although improbable) that the tag could begin transmitting again at some point in the future, or our young osprey may be spotted in the years to come as was the case with Blue YD.
If not then this serves to remind us how perilous an existence the first year of life is for young ospreys, not only on the migration but also on their wintering grounds. We’ll keep you posted if there are any developments.
Meanwhile, there’s been no change to FR3’s behaviour over the past week who remains settled in the bolons (creeks) north of Bulok in the Gambia.
You can view the latest tracking data for yourself visit on our Osprey Tracking page or in Google Earth.