It is with a heavy heart that we have to report that we think Sylvester has died. Looking more closely at the data it seems that the location we received from his tag in the Central African Republic was erroneous - this happens occasionally. In actuallity, we last heard from Sylvester on 28 August in Nigeria, close to the River Niger. We have no clues as to what might have happened to him.

The last location from Sylvester's tag just over a week ago showed that the battery charge was low. We will have to wait and see if this improves to find out where Sylvester is. Fingers crossed he will pop-up soon.

We have received a couple of locations from Sylvester's tag in the last week or so that show he is in Central African Republic. However, the battery charge is low and considering that he is now in an area of dense forest it might not get a good charge for a while - we will have to wait and see what happens next.

We last heard from Sylvester on 28 August and his last transmission showed that his body temperature was fine, which tells us he was alive. However, his battery charge was low and looking at previous data we can see that the battery charge had been falling during the previous week and not recovering. This can happen when our Cuckoos are under the thick canopy in the rainforest and we have lost Cuckoos for as much as six weeks, only for them to pop-up again once their battery gets a good charge.

Of course we don't know for sure what has happened but all we can say is that when we last heard from him he was alive and that there was an issue with the tag which we hope will resolve itself - fingers crossed.

During the last week Sylvester has moved south and east, through Mali, Niger, Benin and into Nigeria. He is just to the west of the mighty river Niger and to the south of a village called Bawanka.

Sylvester has reached the Sahel and the southern edge of the desert. He is currently in the Gao region of eastern Mali and just to the north of the D'ansongo-Menaka Reserve. It is the rainy season and rain is forecast for the next few days, this should provide Sylvester with plenty of food.

When we last heard from Sylvester's tag at just after 5pm on 31 July he was undertaking his desert crossing and was pretty much in the middle of Algeria and about a third of the way across the desert. His tag should power-up again during the evening of 2 August and show whether he has made it across.

Sylvester has crossed the Pyrenees and is in central Spain. He is to the west of the medieval town of Avila. He has Selborne, a New Forest Cuckoo about 70km (45 miles) to his west and Raymond, a Knepp Estate Cuckoo 200km (128 miles) to his east. It will be interesting to see which of these is the first to head south from here.

Sylvester stayed a week in northern France before flying the length of the country and making it to the foothills of the Pyrenees, close to Arudy on 29 June. The next day he moved north again and then west. He is currently in wooded farmland close to Castaignos-Souslens in southwest France.

During the evening of 21 June we received a series of locations from Sylvester's tag that showed he was in northern France, in the area of the Somme close to Amiens.

Sylvester was tagged in Thetford Forest on 3 June. A few days later he left the forest and has spent most of his time since then in the Fens between Littleport, Feltwell and Southery.

Frequenting the area of Thetford Forest just to the south of Cranwich, Sylvester hasn’t  moved very far since he was tagged on 3 June, moving around 4km (2.5 miles) in all directions.