The curlew’s distinctive and evocative call, which echoes the solitude of the estuaries and moorland that it frequents, is a magical sound, and one that has been immortalised in The Seafarer, the Anglo-Saxon poem that dates back to 1,000AD, with its: ‘I take my gladness in the… sound of the curlew instead of the laughter of men’. But sadly, the curlew’s bubbling ‘cur-lee’ call is one that increasingly fewer people, especially those in lowland Britain, can enjoy, with our breeding curlew population declining by 46% in the last 25 years. This decline has also been happening in other countries where they breed, with the International Union for the Conservation of Nature estimating a 20-30% worldwide reduction in curlew breeding numbers during the last 15 years. As a species, it is now classified as ‘vulnerable’ on the European Red List, and within the United Kingdom it is widely regarded as being our bird of highest conservation concern.
The United Kingdom has an important breeding and overwintering population of curlew. We support a fifth of the world’s population that overwinter in our coastal areas and have around a quarter of the world’s pairs breeding at sites in spring and summer. Although curlew were historically a species that could be found breeding on arable land, and in meadows and marshes across Britain, the curlew’s breeding range has become increasingly diminished, with declines in our lowlands being especially dramatic. With only around 250-350 pairs nesting south of an imaginary line drawn through Birmingham, it has become a bird of our uplands, where it breeds on heather moorland, bogs and inbye pastures.
A considerable amount of research into the reasons for the decline in curlew numbers has been undertaken, and from this, it has been determined that the main contributory factor is that of breeding success; not poor adult survival. Curlews return to the same areas to nest year on year, laying their eggs in scrapes on the ground, but the loss, degradation and fragmentation of suitable habitat has taken its toll. Maintaining wet pastures in the lowlands, keeping pastures unimproved, and managing heather on moorland to ensure suitable heights for nesting and cover has become critical for their long-term breeding success.
Nesting on the ground, curlews are particularly vulnerable not just to human disturbance and agricultural nest destruction, but also to high levels of nest predation. A large review of scientific studies across Europe found that 70% of nests between 1996 and 2006 failed to hatch a single chick, and of those that did hatch, only half survived from hatching to fledging. Such poor breeding success is too low to maintain the population. The lawful control of predators such as foxes, carrion crows, stoats and weasels is vital to ensure their survival and stem further decline. However, for this to be successful, it has to be carried out by those with not just the necessary expertise, but also the dedication to work all hours, using all available means to minimise predation pressures.
Whilst recognising the need to undertake predator control to protect breeding curlew and other waders, a recent study undertaken by the RSPB concluded that the means they used in doing so was unlikely to be effective for curlew. That is because their management of predators only involved the limited shooting of foxes and the use of Larsen traps to control crows. In contrast, a recently published paper by the Game & Wildlife Conservation Trust (GWCT) showed how the use of all legal methods for the control of foxes, mustelids and corvids helped minimise predation pressure and contributed enormously to curlew conservation. This is what grouse moor managers have been doing and will continue to do. As a result, the breeding success of curlew is four times greater on moorland that is managed for grouse than that which is not.
What happens to curlew in the United Kingdom will have serious consequences for the global population and we have a pivotal role to play in shaping its future. It is due to the conservation efforts of gamekeepers on managed grouse moors that curlew are now being reintroduced to the South of England. Last year Natural England issued a licence for the removal of 40 eggs from highly vulnerable nests in Wensleydale and Arkengarthdale in the Yorkshire Dales that would either have been in danger of being predated, disturbed by dog walkers or destroyed by agricultural machinery. The eggs were incubated and taken to Arundel in Sussex, with experts hoping that this will lead to the first breeding pairs in the South of England for decades. The project was such a success that Natural England has this year agreed to the removal of 120 eggs from five estates in the Yorkshire Dales, with receptor sites in Kent, East Sussex and Wiltshire.
This is the largest relocation of eggs from an endangered species to have been undertaken. Although still early days, it is hoped that it will reverse the curlew’s decline and re-establish a healthy breeding population in our lowlands where previously it was thought they would face local extinction within the next eight years.
Image: Matt Ridley