BTO: Scientists follow amazing Cuckoos on their journey to Africa

Valentine the Cuckoo, by Lee Barber/BTO

 

As part of a project to discover what might be driving the decline in UK Cuckoo numbers, the British Trust for Ornithology (BTO) has fitted four of these iconic birds with satellite tags. These tags will enable BTO researchers to follow the Cuckoos as they make their way to the Congo rainforest, where they winter, and back again next spring.

Three of these newly-tagged birds are already on the way, crossing the Channel and moving into France within the last few days.Thanks to the continuing miniaturisation of tracking devices, these four Cuckoos are carrying an amazing backpack that will monitor their every move, feeding back information to scientists at BTO headquarters in Thetford, Norfolk.

These Cuckoos have been tagged and named thanks to the generosity of four incredible bird lovers, enabling anyone to follow Senan, Valentine, Tennyson and Nussey via the BTO website as their 5,000 mile journeys unfold over the next few weeks. This journey is full of hazards and will include a crossing of the Mediterranean and a long and arduous flight over the Sahara Desert, before a more leisurely cruise south into the Congo Basin.

By following these four Cuckoos, and another eight birds that are already part of the project, scientists at the BTO hope to get a fuller picture of the pressures these birds face whilst outside of the UK. Each year our migrating Cuckoos face different conditions along the route. The project has been running for eight years – this is the ninth successive deployment – and so far the tagged migrating Cuckoos have faced severe summer droughts in Spain and Italy, unseasonal hailstorms in spring in Spain, sandstorms in the desert and energy sapping headwinds.

The scientists are looking to relate the performance of the tagged cuckoos to the conditions they face to identify what may be contributing to their decline.

Dr Chris Hewson, lead scientist on the project, said, “Before this project began we had no idea where our Cuckoos spent the winter months, or indeed what the journey to get there entailed. Not only do we now have a very good knowledge of both of these but we are also beginning to understand how changing conditions drive mortality rates. By continuing the project with these new birds we will gain more valuable insights into how conditions across the annual cycle, including here in the UK, affect the birds and how this relates to population declines. Each year is different and presents its own challenges to the birds.”

He added, “In fact, every journey that one of these satellite tagged Cuckoos makes is a journey of discovery for those of us that follow them on the way, and it is exciting to know that these four new Cuckoos will add to what we have already discovered and provide information that may well help save their kind.”

One of the strengths of this project has been the fantastic support received from members of the public, many of whom have made a financial contribution to the costs of the tracking devices. All of the BTO Cuckoos can be followed on the BTO website, www.bto.org and can be sponsored for as little as £10, money that will help fund the project going forward.