BTO Study Reveals the Critical Value of Active Management for Curlews

The curlew is one of our most cherished countryside birds, its haunting call a staple of the British uplands. However, across much of the UK, curlew populations have plummeted, with the species now red-listed.

A new research report by the British Trust for Ornithology (BTO), funded largely through the Farming in Protected Landscapes programme, offers a detailed look at how these birds are faring in the Yorkshire Dales.

Focusing on the Bolton Estate and surrounding farms, the study uses modern technology to confirm what many moorland managers have long understood: active management and predator control are vital for wader survival.

High-Tech Tracking in a Traditional Landscape

In 2023 and 2024, researchers fitted solar-powered GPS tags to 19 adult curlews. This allowed the team to track exactly where the birds nested, where they foraged, and crucially, whether they successfully reared their chicks to fledging.

While modern technology provided the data, the success of the project relied on traditional knowledge. Gamekeepers and farmers used their intimate understanding of the ground to help researchers locate territories and nests.

Encouraging Numbers

The results from this part of the Yorkshire Dales are encouraging and stand in stark contrast to the declines seen elsewhere.

• Hatching Success: 60% of the monitored pairs successfully hatched chicks.

• Fledging Success: 38% of pairs managed to get at least one chick to fledging age.

• Overall Productivity: The study estimated 0.62 fledglings per pair per year.

Scientific consensus suggests that a population needs about 0.68 fledglings per pair to remain stable. The figures from this study indicate a "near-stable" population. While we must always strive for better, this is a significant achievement compared to the rapid losses occurring in unmanaged landscapes.

The Role of Keepering and Farming Cooperation

One of the most revealing aspects of this study was where the birds chose to nest. Many successfully bred in "improved grassland" - areas used for silage and hay. Typically, these areas are dangerous for ground-nesting birds due to machinery operations.

However, on the Bolton Estate and participating farms, success rates were high even in these working fields. Why? Because of the collaboration between the estate, gamekeepers, and farmers.

The report explicitly notes that nests in these fields were protected from mowing operations. Furthermore, the area is subject to "intensive predator control" by gamekeepers on the grouse moor and the surrounding fringe land.

The researchers concluded that in areas with landscape-scale predator control, interventions to protect nests from farming machinery can significantly boost breeding productivity.

Staying Local

The GPS data revealed that breeding curlews are homebodies. During the nesting and chick-rearing seasons, they held relatively small territories.

• Most pairs with chicks moved less than 250 metres from their nest site.

• They rarely ventured into different habitats, preferring to stay close to where they hatched.

This highlights the importance of local stewardship. If a farmer or keeper creates the right conditions in a specific field or block of moorland, the birds benefit directly. They are not relying on habitats miles away; they rely on the immediate, managed environment.

Conclusion

This report reinforces the value of the "working conservation" model. It demonstrates that curlews can thrive alongside farming and grouse moor management when the two work in tandem.

The study cautions that these positive results are unlikely to be replicated in landscapes where predator control is absent or where keepering is less intensive. It serves as strong evidence that the time, effort, and financial resources poured into moorland management by estates and rural communities are delivering tangible results for our most threatened wildlife.

Key Takeaway: Active predator control combined with cooperation between gamekeepers and farmers is proving to be the lifeline that allows curlews to breed successfully in the working upland landscape.

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