This summer there will be 15 cuckoos, each fitted with satellite tags, being monitored on their migration journeys to and from Africa by researchers from the British Trust for Ornithology (BTO).
They are part of an ongoing tracking project that the BTO has been running since 2011 to understand the pressures on the birds and why cuckoo numbers have declined by half over the last 15 years and continue to fall. The tags have been fitted to male birds in East Anglia, Sherwood Forest, Dartmoor, The New Forest and Ashdown Forest, as they are larger than females and better suited for carrying the extra slight weight.
The tags have so far provided information new to science. Researchers have discovered that some birds stay in Britain for only about a month each year; that they overwinter in the Congo rainforest; and that each bird uses a different route to get there and back. The initial findings, however, have posed further questions and so, as the project moves into its fourth year, the scientists are aware that there is even more to learn about what influences the successes and failures of the birds' migration. Eventually, this learning will inform what steps need to be taken to improve their chances and save them from becoming further endangered.