It's well known that we have lost over half of our breeding cuckoos during the last twenty-five years. We also know from the BTO/JNCC/RSPB Breeding Bird Survey that Cuckoos are doing better in some areas of the country than in others, with the decline in England (63%) being greater than in Scotland and Wales, but why are they are declining at the rate they are?
Clearly we need to understand all aspects of the Cuckoo’s annual cycle before we can begin to suggest what might be driving the decline.
Whilst the Cuckoo has been well studied during the breeding season here in the UK, once they head off on migration very little was known about the routes they take or where in Africa they spent the winter months. There has only been one recovery of a young bird that was found in mid-winter in Cameroon and that was 82 years ago. If we can pinpoint areas of importance then we can look at whether there are pressures there which could explain the losses of the British Cuckoo.
The development recently of new 5g tags meant that we were able to track this species. In an effort to learn more about the routes and stop-over sites used, our first five British Cuckoos were fitted with satellite-tags in May 2011. See how we caught the Cuckoos. The tags are solar-powered, transmitting for 10 hours and then going into 'sleep' mode for 48 hours, to allow the solar panel to recharge the battery. Read more about the tags here.
So far all of the cuckoos we have tagged, except for Idemili, have been full grown males. This is because they are generally larger than females and juveniles and so are able to carry the tags more easily. Once smaller tags are available, we hope that the licensing body will be able to give us permission to tag females and juveniles and we look forward to learning how their migrations differ from the males we have tracked so far.
Information gleaned from the project will help to form conservation strategies and initiate action. Read about what we have already learnt from the project.
Thank you to all the individuals, organisations and companies have joined in to support this exciting project. Take a look here for a list of all those who have made the project possible, including those who gave advice and volunteers.