Eleven more cuckoos tagged for science

The British Trust for Ornithology (BTO) has fitted 11 more British Common Cuckoos with hi-tech 'backpacks' in order to monitor their movements.

One of the most iconic sounds of summer, three-quarters of England's Common Cuckoos have disappeared over the past 25 years. While the species has increased substantially in Scotland, the overall British breeding population has halved over that time.

The BTO first began following cuckoos on their migrations in 2011, initially to discover where they went for the winter months and the routes they might take to get there. It was found that they winter in and around the Congo basin and get there via Italy or, for some cuckoos breeding in England, Spain. The survival rate on these two routes also proved to be very different, with more birds surviving on the Italian route than the Spanish one and that this difference appears to be contributing to the population decline in England, although the reasons for it are unclear.

Eleven Common Cuckoos have been tagged across Britain this summer (Jonathan Rosborough).

Early indications are that it might partly be related to conditions in the UK putting English cuckoos at a disadvantage even before they begin their 5,000-mile journey south. It is hoped that the 11 tagged birds making up the 'class of 2021' will help build knowledge and identify where the problems lie.

Dr Chris Hewson, who runs the project, commented: "We have been following an incredible cuckoo called PJ for the last five years. He's migrated more then 75,000 km during that time and is still going strong, but many of these new Cuckoos will not fare so well. Some will be lost as they migrate across Europe for the first time, and how each fares will help us understand how the conditions they encounter and the pressures they face along their migration routes interact and contribute to population changes. Having tagged some birds in Scotland and Wales this year, it will be especially interesting to see how birds tagged in different parts of  the UK fare."

The Cuckoos had their satellite tags fitted in Warwickshire, Nottinghamshire, Norfolk, Wales and Scotland, and all have been given names: Columbus (Scotland), Ellis (Scotland), Grove (Norfolk), Victor II (Scotland), JAC (Wales), Calypso (Worcestershire), Attenborough (Norfolk), Harry (Worcestershire), Clive (Worcestershire) and two to be confirmed.

You can follow the progress of the cuckoos, including long-lived PJ, at www.bto.org/cuckoos.