Updates from our Cuckoos

As suspected, David has moved on quickly from his position on the south coast and transmissions received early this morning show that he is back at Tregaron, the site where he was originally tagged. He is the only tagged male Welsh Cuckoo to have made it back. There are concerns for our other Welsh bird, Lloyd, who also wintered in the Democratic Republic of Congo as transmissions show he has not continued on from Morocco. 

David was still in the Centre region of France on 2 May but by the evening of 6 May he had covered 345km (215 miles) and was on the north coast of France, close to Cherbourg. Three hours later and he had covered around 114 km (71 miles) across the English Channel and was 40km (25 miles) south of Bournemouth. Shortly after this, further transmissions indicate he made landfall.

When David’s tag resumed transmissions yesterday afternoon (Wednesday 17 April) we were delighted to see that he had completed his desert crossing and was in Extremadura, Spain! He has stopped in an area of open olive woodland, about 27km (17 miles) due N of the town of Cáceres.

David had travelled an additional 1885km (1171 miles)slightly east of due N since he was in the Mauritania desert two days previously. He appears to have taken the short route across the desert, west of the High Atlas and along the Moroccan coast, as we had thought he and BB might do. We don’t know why he had stopped in the desert at the time of the last transmissions, but we guess that it may have been due to adverse conditions, possibly wind or dust-related.

David has been in central Spain for six days now. He is currently 120km (75 miles) south-west of BB, and we are due to hear from him in the early morning of 24 April - might he have moved north?

As hoped, David’s faltering tag has charged well enough for transmissions to resume during his desert crossing.  Four transmissions were received this morning placing him in north-western Mauritania, close to the border with Western Sahara. Unfortunately, all four placed him in approximately the same place and he doesn’t appear to have moved at all during the three hours after dawn. Although we have seen cuckoos stopped in the desert during the day only to resume migration and successfully complete the crossing, it would be very unusual for one to do this so early in the day. We are concerned about this situation but hope for good news when David’s tag begins its next transmissions on Wednesday.

We didn’t hear from David’s tag during its last scheduled transmission period yesterday, which is in keeping with the poor charging and erratic transmissions of the last few months. We hope his tag will last long enough to enable us to track his return to Britain – hopefully when he moves across the desert, it charge well enough for transmissions to resume. 

With no signals from David for 2 weeks, we were stating to get concerned, although on his last transmission we could see his battery was very low and that he was still alive. He has now transmitted from Sierra Leone and is very close to the northern border with Guiena. From being the most easterly of the tagged Cuckoos, with his last known location in Cameroon, he is now the most westerly. Around 2650 km (1650 miles) separate these two locations and it’s likely he will have stopped once or twice in between these two points. Both David's and BB's current locations (in Sierra Leone and Guinea respectively)  are the first time we have recorded any of the tracked cuckoos west of Britain during spring migration. If they cross the Sahara directly from here to Morocco or western Algeria and then move on to Spain, they will effectively have re-traced the westerly route that we have seen some of the cuckoss tagged in England take in autumn. This would be especially surprising in the case of David, given that he wintered quite far east in the DRC.

Lloyd has now left David well behind, in Cameroon. It is now ten days since we heard from David’s tag so we hope to hear from it soon. When the last message was received, the temperature indicated that all was well with David but his tags’ charge was extremely low – it has been since early September, including in periods when it should have been exposed to plenty of sunlight, and the tag has apparently been having charging less well than the tags on other cuckoos. We hope that it will spring into life once David moves to a bright, sunny location but it is possible that the battery has degraded to a point beyond which this is possible. We will have to wait and see….

None of the Cuckoos began crossing the Sahara, as anticipated, over the Easter weekend but we still expect them to make a move soon. Stay tuned for further updates when we get news of any movements.