Cuckoo Tracking Project

Cuckoo. Alan McFadyen

Help us follow Cuckoos on migration and discover why they are in decline.

We’ve lost over half the number of Cuckoos in the UK over the last 20 years.

Since 2011 we’ve been satellite-tracking Cuckoos to find out why. We’ve learned lots of vital information which could help us to understand our Cuckoos, such as how the different routes taken are linked to declines, and some of the pressures they face whilst on migration — but there is still more to discover. We now need to look more closely at how dependent they are on, and how much their migration is linked, to the drought-busting rains of the weather frontal system known as the Inter Tropical Convergence Zone (ITCZ) as they move out of the Congo rainforest and begin to head back to the UK via West Africa.

Follow our Cuckoos as they move to and from Africa.

This project wouldn't have been possible without the amazing support from funders and sponsorsRead more about the project and find out how you can get involved.

We have been able to share our expertise around tracking Cuckoos with other international studies, such as the Beijing Cuckoo Project.

Skill required

  • Follow our Cuckoos on the map below - use the controls to animate or step through their movements.

Cuckoo movements from 01 May 2020 to 09 May 2021

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Current Cuckoos

Carlton II the Cuckoo Carlton II the Cuckoo

Carlton II

Status: active
Cuckoo 161318 portrait Cuckoo 161318 map marker


Status: active
Valentine the Cuckoo Valentine the Cuckoo


Status: presumed dead

View previously tagged birds

Latest updates

PJ is back again!

24 Apr 2021

After five years and a staggering 50,000 miles, Suffolk Cuckoo PJ has once again returned from Africa to his breeding grounds in the King's Forest, Suffolk. He is the first of our tagged Cuckoos to survive five complete migrations with his tag still functioning. When we last updated you he was having a well deserved rest on the Isle of Wight, but despite the many attractions of that fine place, it couldn't keep him away from East Anglia for long. New updates received from PJ's tag at 07:30 yesterday morning (Friday 22nd April) showed that he had covered the final 223km (139 miles) from the Isle of Wight to Suffolk. Further updates since show him flying around his breeding grounds, less than 5 miles from us here at BTO HQ in Thetford. He will stay here until early July before beginning his journey back to Africa once again.

PJ takes a break on the Isle of Wight

22 Apr 2021
New updates received from PJ's tag just before lunch yesterday (Wed 21st April) showed that he had flown 866 km (539 miles) north, over France and across the English Channel to his new location on the Isle of Wight. We received further updates from his tag yesterday evening showing him in the same area, on farmland close to the village of Havenstreet, just south west of Ryde. It is now just 223 km (139 miles) as the Cuckoo flies, back to his breeding grounds in the King's Forest, Suffolk. In previous years he has arrived back at his breeding grounds between 18th and 30th April so he is being very punctual. When we next update you, it will hopefully be to tell you that PJ has successfully made it "home".  

PJ getting closer

19 Apr 2021
Updates received from PJ's tag just after 5am this morning show that he has flown a further 371km (231 miles) north east into northern Spain. He is now close to the shores of the Urranaga Reservoir, some 40km south east of Bilbao. How long will he linger before flying on? We will be keeping a close eye on the weather forecast over the next few days to spot likely opportunities that PJ may take to press on. Stay tuned!

Browse updates from our Cuckoos

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Project timeline, contributions & findings

Project timeline

  • 5/11 - First round of five Cuckoos tagged, wintering sites in the Congo identified 
  • 3/12 - Different routes discovered on return journeys
  • 2016 - First scientific paper published on on the routes of our Cuckoos

Support the project

You can help keep this important project going by either giving a donation, becoming a Cuckoo sponsor, or gifting a sponsorship to someone else. We greatly appreciate the support the project has received, allowing us to continue to monitor this endangered species.

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