Updates from our Cuckoos

When Chris’ tag resumed transmissions as the skies cleared on Saturday evening (13 April), two locations showed he was still south of Autun in Burgundy, central France. Between the times of the two locations, however, his tag’s temperature dropped by 4 degrees C, probably indicating the initiation of migration, and sure enough, an hour and a half later he was 80km (50 miles) to the NNW. In total, Chris advanced about 120km (75 miles) in the 3.5 hours after dusk. Further unconfirmed locations for the early hours of Sunday morning suggested that he had stopped about 80km (50 miles) to the east of Paris, possibly due to the rain that lay to his north. If indeed he did stop here, we expect he would have resumed his migration the next night so it is likely that when his tag comes on again on Tuesday morning, he will be back in England – watch this space!

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. 

Locations received this morning (Thursday 11 April) show that BB is still in the Upper Niger NP in Guinea. He is within a few kms of both the upper reaches of the Niger itself and its confluence with a major tributary. Both watercourses are already quite large this far upstream (the Niger is over 100m wide), reflecting the very high rainfall that areas upstream in this corner of West Africa receive each year. 

A good location received in the early hours of this morning shows that Lloyd remains at his previous location in eastern Ivory Coast, 50km SW of Comoé NP, in the same area that was used by BB and Chance early this spring and by Martin last year. 

Chance could still be next to make the desert crossing but at the moment unconfirmed signals suggest he is still in the Ivory Coast. 

Signals received yesterday morning show that Chris has continued quickly onwards from Italy and is already in France, travelling 450km (280 miles) to Charbonnat in southern Burgundy with little rest. This has been a very fast paced journey from Ghana - Chris has covered about 4,600 km (2858 miles) in less than a week, which is not much slower than the fastest of the swifts we have tracked with geolocators! If he is still in good condition and the weather is kind, he could be home in the next few days. 

Transmissions from Lloyd's tag yesterday show that he is also moving west. He has covered 185 km (115 miles) in a north-westerly direction from his location in Ghana and is now in Ivory Coast. Will he cross the desert from here or follow BB and David even further west?

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.