Updates from our Cuckoos

Chance, Lloyd, David and Chris all remain in their previous positions according to locations received in the last two days.  

So far in 2013, we have heard from four of the five remaining Cuckoos. We received tag transmissions from Chris and Chance today and from Lloyd and David yesterday showing there had been no substantial movements to report.

However, we haven’t heard from BB since the 30 December - at this stage this is nothing to worry about, though, as at this time last year we regularly went longer than this without hearing from the Cuckoos. A combination of poor charging conditions and a gradual decline in battery charge mean that they are transmitting less often, whilst as they are within the forest interference from trees reduces the chances of transmissions being picked up by satellites. Once they move on, or the weather at their current locations improves, we should start to receive positions more regularly again. 

David's tag last transmitted on the afternoon of 31 December indicating that he had remained in the same area. We hope to receive another transmission shortly. 

David has travelled south from the swamp forest. On the 22 December a transmission revealed he was 116 km  (72 miles) south from his previous position and by the 24 December he had continued 39 km ( 24 miles), crossing the Lukenie river. He is now close to the position he held on the 6 December, on the edge of the forest zone. A further signal recieved this morning indicates he is still in this area.

Last week we wondered whether David was heading for the savannah-forest mosaic just to the south of his latest position. It appears the answer was no! Between Thursday 6 and Saturday 8 December, he moved around 160km (100 miles) approximately NW from his previous position – this movement has taken him away from the edge of the forest zone into an area dominated by what looks like swamp forest, although it is hard to be sure form the Google earth map. We wonder whether David is actively seeking this kind of habitat (as Chris appears to have done) or whether he was simply not aware of what habitat lay in front of him before turned around. 

Now that BB has moved south, the five Cuckoos that we are still tracking all appear to be at, or close to, their final wintering locations. Although we can’t draw firm conclusions from such small numbers, the Scottish-tagged Cuckoos are wintering in the same area as the Cuckoos tagged in England (bar Chris) did last winter. The two Welsh Cuckoos are further to the east. This is really interesting but whether it reflects general differences in the wintering areas used by the different breeding populations will need to be confirmed by the results of further tracking work in the coming years.

David has moved about 80km (50 miles) south-west from the location in southern DRC that he held since about 18 September. He is still in an area dominated by continuous rainforest but has now has crossed the Lukenie River and is only 50km (31 miles) from the Kasai River at Mangai, which marks the boundary between the rainforest and forest-savannah mosaics in this area. It will be interesting to see whether he stays here for long or continues further south into the area of habitat that is much more similar to where the other Cuckoos (save Chris) are now and where the Cuckoos last year also spent winter.

It is notable that the two Welsh-tagged Cuckoos are to the east of the areas occupied by the Cuckoos tagged in England and Scotland both this and last winter. The very small numbers of tagged birds involved make it difficult to draw firm conclusions but this may reflect slightly different wintering locations for these populations. 

David is still in the same place within Democratic Republic of Congo that he has been in since 24 October and is still the most southerly of all the Cuckoos. We received transmissions from his tag yesterday.

There are currently just five tagged Cuckoos from which we are still receiving regular transmissions. While BB, LLoyd and David have all transmitted in the last couple of days, none of them have moved from their previous positions. Chris's tag transmitted on 7 November and showed he had made a small movement south of about 34km (21 miles), taking him closer to the Ubangi river. Chance also seems to have made a small movement recently and is now south-west of the Faro Reserve and only 54km (34 miles) from the border with Nigeria.