The Dartford Warbler bounces back from the brink of UK extinction

The most recent national survey has now revealed the highest ever number of Dartford Warblers recorded on RSPB nature reserves, with 264 pairs counted in 2025 – that’s a 44% increase in just five years! The wider UK population estimate has also reached 4,100 pairs, up from 3,200 during the last national survey in 2006.

Last year, the RSPB worked with BTO and Natural England to carry out the UK-wide Heathland Birds Survey, which aimed to update the range and population estimates for the Dartford Warbler and other heathland birds. Thanks to the invaluable support of surveying volunteers, we have been able to update the previous figures, which were almost 20 years old. These new results help to assess how effective heathland management is for these species.  

Previously facing extinction in the UK, only a handful of pairs, limited to Dorset, remained just over 60 years ago. Now, with an estimated 4,100 pairs in total and a record-breaking year on our nature reserves, there is hope that effective conservation is helping the recovery of Dartford Warblers in the UK. 

A small, charismatic bird often seen perched on top of gorse singing a scratchy song, Dartford Warblers are found on lowland heathland in southern England. They are grey-brown in colour, with a distinctive red eye ring, russet breast and long tail. These birds are particularly sensitive to harsh winter weather and, as a ground-nesting species, heavily rely on dense gorse within areas of mature heathland for vital food, shelter and protection.  
 
Gorse – a tightly packed, spiky shrub – provides a safe nesting place and hunting ground for Dartford Warblers, which specialise in picking spiders and caterpillars from their hiding places.  

Lowland heathland is one of the most threatened habitats in the UK with 80% lost since the 1800s due to forestry and land-use change. To tackle this, dedicated RSPB staff and volunteers have been restoring the precious habitat on nature reserves by removing conifer plantations and reverting arable land. Joining up areas of fragmented heathland provides Dartford Warbler with the vital dense gorse they need to thrive.  

The Dartford Warbler’s remarkable bounce back is a good indication of the health of these habitats.  

Dartford Warblers were recorded at 14 RSPB nature reserves including an incredible 97 pairs at RSPB Arne, a record for the site. Alongside heathland management, the team has also started the process of converting a further 15ha of farmland to heathland. 

RSPB Arne site manager, Peter Robertson, said: “Restoration of heathland across RSPB Arne has been on a truly landscape scale. Staff and volunteers have helped connect and enlarge fragmented patches of precious heathland to give wildlife, such as the distinctive Dartford Warbler, the space to thrive. Visiting heathland during summer, the sound of Dartford Warblers singing is everywhere. Being able to hear those calls is the perfect reminder that the hard work is paying off. Helping to maintain then increase numbers, and reverse population declines of species like the Dartford Warbler is very rewarding.”   
 
Other pairs were also counted at RSPB Aylesbeare (25), RSPB Minsmere (41), RSPB North Warren (17), RSPB Farnham Heath (23) and RSPB Broadwater Warren (15). The latter two reserves were conifer plantations just 20 years ago, demonstrating what a transformative impact habitat restoration can have for wildlife. 

Dr Greg Conway, Senior Research Ecologist with BTO, said: “Volunteer participation is key to the success of such projects, and we are truly grateful to all the people who contributed to the Heathland Bird Survey in 2025. The results clearly show just how well managed protected areas are essential for the recovery of these, and other habitat specific species. With the creation and improvement of more suitable sites, we can hope to see continued range expansion, and population increases in the future.”