Cuckoo Tracking Project

Help us track Cuckoos and learn even more about their epic migration

We’ve been satellite-tracking Cuckoos since 2011. We’ve learned lots of vital information, such as how the different migration routes are linked to declines, and some of the pressures Cuckoos face whilst on migration, but there is still much more to discover.

We have been able to share our expertise around tracking Cuckoos with other international studies, such as the Beijing Cuckoo Project.
Read more about our Cuckoo Tracking Project.
Explore the Cuckoo BirdFacts page to learn more about this iconic species.

An important aspect of this project is how it helps us improve our understanding of why Cuckoo are in decline:

Since 1995, the number of Cuckoos has decreased by over 30%.
The Cuckoo is currently Red-listed as a Bird of Conservation Concern in the UK.

Our Cuckoo Tracking Project is vital and it wouldn’t be possible without the amazing support from funders and sponsors.

Sponsor a Cuckoo

What’s next

We now need to look more closely at how dependent Cuckoos 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.

Watch the Cuckoos migrate on our map

Each Cuckoo’s tag sends us location data approximately every day, so we can follow them and learn more about their migration.

Time / skill required

Spend as much time as you like following each Cuckoo's migration on the map below - use the controls to animate or step through their movements.
No technical skills are required to support this project - just a love of Cuckoos.

Cuckoo movements from 01 May 2024 to 25 April 2025

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Latest updates

Sayaan sails into Sussex

25 Apr 2025

Hot on the heels of Cores and Wilfrid, Sayaan is the third of our tagged Cuckoos to return to his breeding area this spring.

Having made his way through the Italian Alps from Genoa, via Turin, in recent days, he then took off through France in a north-westerly direction, passing Paris and heading directly for The Channel. Around 7.30 this morning (25) he flew over Worthing and continued inland and is currently just south-west of Horsham, West Sussex.

He is in the same region where he was tagged in 2023 and where he also spent last summer.

Hafren's homeward bound

25 Apr 2025

In the last three days Hafren has left his temporary home in the Cáceres province, Spain, and covered around 1,600 km (994 miles). His journey took him around the Bay of Biscay, passing over Bilbao, then Bordeaux, before heading to Nantes, and finally taking a rest just north of Lorient, in southern Brittany.

His next big flight should take him to the UK and to his Worcestershire summer residence!

Joe Cool takes it slow

25 Apr 2025

Joe has now left Spain, and is the only one of our tagged Cuckoos to cross over the Pyrenees, though he took it relatively easy by keeping to the west and avoiding the higher mountains! Passing Pamplona and entering south-west France, he is currently in lush farmland in the Nouvelle-Aquitane region.

Tagged in East Anglia back in 2022, he arrived back on his regular breeding grounds on April 29 last year, and on April 24 in 2023. Will we see him back on Norfolk soil this weekend?

Browse updates from our Cuckoos

Project Lead

Chris Hewson

Email Contact:

cuckoos@bto.org

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

Contributions & findings

Cuckoo declines linked to different migration routes to Africa

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.

Our Cuckoo tracking journey

Senior Research Ecologist Chris Hewson reflects on 13 years of catching and tagging Cuckoos, and why it’s vital that the project continues.

Publication

Fidelity and distance to previously visited sites throughout the annual cycle in a trans-Saharan migrant, the Common Cuckoo

Research in collaboration with BTO scientists has used data from satellite-tracked adult male Cuckoos to show that although all birds returned to the same breeding grounds in consecutive years, the

News

2023’s Cuckoos are tagged and ready to go

BTO has fitted 10 more Cuckoos with satellite tags, allowing scientists and the general public to follow these incredible birds on their annual migration.