1. Flagship BTO project Cuckoo tracking
The most high-profile project currently being undertaken by the BTO is its Cuckoo-tracking work.
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 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, five British Cuckoos were fitted with satellite-tags in May 2011. 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.
Information gleaned from the project will help to form conservation strategies and initiate action.
Cuckoo tracking

2. Here are the journeys of the five Cuckoos tagged in May 2011.
Two – Chris and Lyster – made it all the way back to the UK again to breed in We don’t know if the tags failed or if the Cuckoos died but with a survival rate of 60% (shown from ringing data) this was a pretty good result!
This work reveals the routes taken by Cuckoos on migration in unprecedented detail.
Cuckoo tracking

3. Class of 2012 Cuckoo tracking
The rate of decline of Cuckoos has been different in England, Scotland and Wales. In 2012 the BTO tagged 12 more of these birds (note, Chris and Lyster were already tagged) to compare their migratory routes, including birds from Scotland and Wales (2011’s birds were just from England).
Most of Class of 2012 failed to make it to the African wintering grounds, in contrast to the Class of For example, Wallace disappeared in Italy which we think was due to a tag failure. Mungo and Lyster made it to the Sahara and then went missing for unknown reasons so we don’t know if it was the tag or that they died.
Some Cuckoos made it to the Congo but didn’t make it back – for example Lloyd made it to Morocco. His tag was continuing to transmit but he didn’t move, suggesting that he perished.
At the end of 2012, 9 of the 14 Cuckoos failed to make it back or had tags malfunction.
Chris the Cuckoo, name in honour of Chris Packham, was the only Cuckoo to survive both the 2011 and 2012 migrations.
Cuckoo tracking

4. Class of 2012 Cuckoo tracking
Comparing the three different regions – Wales (red outlines), Scotland (yellow outlines) and English (blue outlines)
The majority of Welsh birds (red) travelled much further east than Scottish (yellow) or English (blue)
Cuckoo tracking

5. Class of 2013 Cuckoo tracking Still active (April 2014) Missing
A further 14 Cuckoos from England and Scotland were tagged in Of these so far 6 are missing, all on the journey out, with 5 presumed dead for various reasons. For instance Dart stopped in Mallorca and there were reports of a wildfire. Ryder failed to cross the Sahara and it is thought that he didn’t have enough energy resources to make it over.
However, there are 11 Cuckoos currently on their way back, though only Skinner has attempted to cross the Sahara so far (07/04/13). Chance, we’re unsure about – he and Tor went missing at the same time in December, but Tor’s tag started working again in April – we think it may have run out of solar power. The hope is that Chance has the same. None of the tracked Cuckoos have died in the over-wintering period so it is more likely a tag malfunction than due to death.
Cuckoo tracking

6. Class of 2013 Cuckoo tracking
Interesting to see, in the 3rd year of Chris’ migration, that he more or less follows the same route every year
Cuckoo tracking

7. Class of 2013 Cuckoo tracking
We have a live Google map at
Cuckoo tracking