Spring is the time for bird song, but not just in the garden. On the coast and up on the moorlands you can hear the haunting call of the curlew. The song accompanies an ‘air dance’ where they fly up above their territory and then parachute down, all the while emitting the song that gives them their name.

It’s an impressive sight as, with a 40in (100cm) wingspan, and weighing up to three pounds, curlews are the largest of our wading birds. It is also an impressive sound that has inspired writers since its first mention in a manuscript of 1000 AD. In more recent times (well, the 1700s) Robert Burns wrote that he had “never heard the loud solitary whistle of curlew… without feeling an elevation of soul”.

It would be tragic to lose such a soulful song, but the sad truth is that our curlews are in trouble. The British population has fallen by over 50 per cent in the last 20 years, making it the number one bird conservation issue. We have about 25 per cent of the global breeding population. In winter those numbers are swollen by European birds who migrate here from colder climes. This makes Britain the most important place in the world for curlews.

The reasons for this rapid decline are complicated. Curlews need grassland and wetland areas in which to breed and feed. Both these habitats are being lost to forestry, drainage and increased grazing. Having more livestock on curlew territories often leads to nests being trampled or, odd as it sounds, eggs being eaten by sheep, who seem to like a more varied diet than we thought. On top of that, climate change is drying out some wetlands and flooding other areas.

Curlews also suffer badly from predators such as ion. While they need particular habitats to survive, crows and foxes are famously adaptable and thrive anywhere. This creates an imbalance of predators to prey that seriously depletes curlew numbers.

The key to helping this beautiful bird lies in trying to reclaim and protect the land on which it lives, tipping the balance of nature back in the curlews’ favour. This is something that Cumbria Wildlife Trust and other organisations are trying to do.

April 21 is World Curlew Day, a global initiative to raise awareness of their plight. Look online to learn more and see how you can do to help. And if you are out on the fells or moors, listen out for the clear, calming call of these beautiful birds. Once you hear it, I think you’ll agree that they are well worth saving.