Following the Cuckoo beyond the summer song
Newly tagged Cuckoos from England, Scotland and Ireland are preparing to leave their breeding grounds, as BTO scientists continue a 15-year project to uncover the hazards facing one of our most familiar declining summer migrants.
Satellite tags reveal an early departure
The UK’s breeding Cuckoos are already beginning to leave for Africa, with some birds preparing to set off after spending only a few weeks on their breeding grounds.
Although the Cuckoo remains one of the most recognisable birds in Britain and Ireland, its call is now heard less often than it once was. According to the British Trust for Ornithology, the UK has lost more than a third of its breeding Cuckoos over the last three decades.
For 15 years, BTO researchers have been using satellite tracking to understand where these birds go, which routes they take and what pressures they face during their long migrations between Britain, Ireland and central Africa.
More than 140 Cuckoos tracked since 2011
The project began in 2011 and has now seen satellite tags fitted to more than 140 Cuckoos from across Britain and Ireland. This spring, BTO ornithologists have again been catching and tagging birds in Scotland and England, while colleagues from Ireland’s National Parks and Wildlife Service have been doing the same in Ireland.
The new birds will join previously tagged Cuckoos whose movements are already helping scientists build a much clearer picture of the species’ migration. In addition to satellite tags, nine Cuckoos have been fitted with highly accurate GPS tags, allowing researchers to examine their routes and habitat use in greater detail.
Before this work began, little was known about the Cuckoo’s migration routes, and its wintering areas south of the Sahara were unknown. The project has since shown that birds from Britain and Ireland use two main routes to reach the same wintering grounds in tropical Africa.
Two routes, but very different survival rates
All Cuckoos tagged in Scotland and the uplands of Wales have taken an easterly route through Italy on their southward migration. These birds have shown a significantly higher survival rate than those travelling west through Spain.
Cuckoos from other parts of the UK may take either route, but the BTO research has found that birds from lowland England using the westerly route have the lowest survival rates. Late-departing birds from these areas appear to face particularly high risks.
The tracking work has also changed understanding of the species’ timing. Male Cuckoos can begin their southward migration by early to mid June, after spending as little as six weeks in their breeding areas.
The Cuckoo cohort of 2026
The newly tagged birds include five Cuckoos from Britain and three from Ireland.
- Cuckoo Crispin - tagged at High Lodge in Thetford Forest and funded by a generous BTO donor.
- Cuckoo Rob - tagged in Kintail in the Scottish Highlands and named in memory of the tag funders’ late friend, Rob Watson.
- Cuckoo Beech - tagged in Thetford Forest and named after one of the tag funder’s favourite tree species.
- Cuckoo Thomas J - tagged in Kintail in the Scottish Highlands and named by the tag funder in memory of Thomas Joseph Paul, a well-travelled engineer and gentleman with a lifelong love for the Scottish hills.
- Cuckoo 40926 - tagged in Kintail in the Scottish Highlands and awaiting a name. BTO says anyone interested in funding his tag, at £4,000, should get in touch.
Irish birds
- Cuach Sean - tagged at Derrybawn in Wicklow National Park and named after the tag funder’s son.
- Cuach Rua - funded by NPWS and named after Slieve Rua, a hilltop in Burren National Park close to where he was captured. Rua also means red in Irish.
- Cuach Avala - funded by NPWS and named after Lough Avalla, close to where he was tagged in Burren National Park.
Understanding the pressures on migration
Dr Chris Hewson, lead scientist on the project, said it was encouraging to see more Cuckoos setting off with new satellite and GPS tags.
“These birds will help provide the information that we need to better understand the challenges these remarkable birds face, and how we may best help them to successfully complete their incredible and arduous migrations, in a rapidly changing world,” he said.
The latest tagged Cuckoos are expected to begin their southward journeys in the coming days and weeks, adding further detail to one of the longest-running studies of Cuckoo migration in Britain and Ireland.
June 2026
Get Breaking Birdnews First
Get all the latest breaking bird news as it happens, download BirdAlertPRO for a 30-day free trial. No payment details required and get exclusive first-time subscriber offers.
Share this story
