Hennah's tag battery is damaged and appears to be failing - consequently we have not received a good quality location from it recently although poor quality locations showed him in France on 16 June and heading south to Italy a few days ago.
We last received a signal from Hennah's tag in late Februay from Sierra Leone, from where he had moved to on the 10 February. No further signals were received and we could tell the tag was not charging well so imagine our surprise when on the 15 April Hennah reappeared in the UK, north-east of Bournemouth, becoming the first Cuckoo to return home!
BTO scientist in charge of the project, Chris Hewson, explained that this lack of signals over the desert, when we might expect good exposure to the sun, could be down to the Sahara dust on the solar panels which meant the tag was unable to charge and send a signal. Exposure to rain later would then have washed this off and allowed the tag to transmit his recent location.
Hennah has settled in an area of close rainforest in Gola Rainforest National Park - a world famous national park and UNESCO World Heritage Site. Since he settled here, his tag has not been charging well, due presumably to the dense rainforest canopy. When we last received a signal from his tag the charge was low but the temperature showed that Hennah was alive and well as far as we can tell.
Two of our tagged Cuckoos are already moving west and are well on their way back to their breeding grounds in the UK!
Hennah had moved 2500km (1500 miles) to Ivory Coast by 8 February from a position on the northern forest edge on 6 February, low quality signals tell us, but by the 9 he had already continued west a further 820km (510 miles). He is now just inside the border of Sierra Leone in an area where the Lofa-Mano National Park and Gola North Forest Reserve meet, where presumably he will rest for a while after such a long journey in such a short amount of time.
Meanwhile, Ash was in Nigeria on the 8 February but by the 9 he was in Ghana, north of Lake Ghana and the Digya National Park.
Although this is not especially early for them to move into the region - in previous years we have seen the first cuckoos move to West Africa by mid-February - Hennah's stopover location especially is very far west for the date, as early stopovers tend to be further east. It is notable that both stopovers are within the humid forest zone, rather than to its north as most West African stopovers are - this could compensate for the birds being so far west at this time, before the savannahs in the area have been rained upon.
Several of our Cuckoo tags have not sent transmissions for over 10 days; BB, Hennah, Peter, Skinner and Waller.
This means they are not currently shown on the main map by default, although can be switched on using the tick boxes under their photos. It's not uncommon for Cuckoos to disappear for up to several months during mid-winter as tag charging conditions in the forest are poor so we won't really know their fate unless we receive further transmissions. If they fail to move northwards when expected then either the Cuckoo may have died or the tag may failed or degraded. Our greatest concerns are still for Peter and Waller who were in the same area when signals were last received, all the way back in October.