On 5 March we received one good signal from Fred's tag which showed that he had moved to the northern forest edge, where many of our tagged Cuckoos have moved to before heading to West Africa.  

From time to time we ‘lose’ one or two of our Cuckoos only for them to reappear several days, or even weeks, later. We are never entirely sure why this might be at the individual level but during the course of the project we have noticed similarities between some of the ‘lost’ birds.

We have lost some of our birds just prior to them making a large movement and we think that this might be because they move into denser vegetation in order to feed up before embarking on a long flight. Moving into denser vegetation may mean that the solar panel that recharges the battery for the tag is in shade for periods of time and the battery receives a poorer charge, which in turn results in poorer performance from the satellite tag.

Once the birds have put on enough weight to begin their journey they move into the open and the tag begins charging again and the birds ‘reappear’. We also see the same thing happen, although to a lesser extent, when birds complete a long movement and presumably move into denser vegetation to rest and feed up

There have been a few small movements recently. Fred and Jake have moved west into Congo whilst David has moved into the area that Emsworthy has left. 

These are likely down to changing rainfall conditions which may affect food availability and cause the Cuckoos to seek areas which may be more plentiful in resources. It will be especially important to find a good feeding area before they make any move northwards. There's no consistent direction in which these Cuckoos leave an area and one Cuckoo may move from an area only to be replaced by another moving in from elsewhere, with no obvious reason why.

Fred and Jake, two of our Cuckoos tagged in Sherwood Forest, have moved westwards and are now in Congo. Fred recently left the Mbandaka area and has moved about 270km (165 miles) west from his previous location in Democratic Republic of Congo, while Jake, who is about 70km (45 miles) further south, travelled a shorter distance of 155km (95 miles). 

Interestingly, Derek who is slightly further north, had been moving east, the opposite direction to Jake and Fred, until recently but he has backtracked around 65km (40 miles). Emsworthy has also moved, but northwards to the area not long vacated by Fred. These movements may indicate changing conditions which are encouraging the Cuckoos to seek more favourable areas. 

From his position in Congo, Fred had moved east and into Democratic Republic of Congo by Christmas Eve and was close to the River Congo. He remained in the area until 12 January before then moving 145km (90 miles) west, crossing back into Congo but remaining in the area of swamp forest.