The Zambian based Cuckoo did the trip to Mongolia. Amazing journey. It's Congo based cousin did the trip to the UK and is about to return for it's 6th journey. The tag to track the Cuckoo costs £3,500 each and £60 per month to monitor it progress. BTO netted 11 across the UK over the last two months. 3 have left the UK and are in Normandy, west of Paris and in The Netherlands. A large investment to understand an endangered species.