Bluebell time at Broadhead Clough: sweet-smelling flowers carpet this Pennine woodland, daubing its green glades with patches of blue.

It’s a spring spectacle to gladden the heart: well worth the steady climb from the valley bottom near Mytholmroyd in Yorkshire’s western fringes. But it’s not the main reason I’ve come here on this surprisingly chilly May morning. I’m hoping to spot a legendary bird that, like the bluebells, can only be seen in Britain for a few weeks each year.

Cuckoos arrive on our shores in late April after a 5,000-mile migration from central Africa. By early June, they’re already embarking on the long trip back. The male’s call – a loud declaration of his own name – is probably the most recognisable two syllables in British birdsong. It’s certainly one of the most distinctive sounds of spring, steeped in folklore and famously inspiring letters to the Times from readers vying to record the birds’ first arrival each year.

 But, sadly, far fewer of us are getting the chance to hear them, and there’s a real danger that they’ll be lost to future generations. The number of cuckoos in the UK has plummeted by an alarming 77 per cent since 1965, and they’re classed as red-listed, meaning they’re globally threatened.

If you’re keen to see one, Broadhead Clough is one of the best places in Yorkshire to visit. The nature reserve’s rare wet woodland bog areas – criss-crossed by small streams and littered with fallen trees – allow moss, liverwort, wetland plants and fungi to flourish. This provides ideal conditions for the larvae of many invertebrates – perfect food for cuckoos.

I walk on through the trees, crossing one of the boggiest mires on a boardwalk and then climbing steeply up a series of old, stone steps. I can hear plenty of birds – the raucous shriek of a jay, the soft, delicate song of a goldcrest, the indignant squawk of a pheasant – but not the one I’m listening out for.

After this energetic uphill section, I give my legs and lungs some respite by branching off on a more level footpath towards the eastern side of Broadhead Clough. That’s when I hear it:

Cuck-oo! Cuck-oo!

It’s quite faint, but unmistakable – and it’s coming from the direction I’m heading in. I stride on with renewed purpose…and encounter a distraction.

A roe deer comes pelting down the wooded hillside to my left, sprints across the track and disappears from view. The harsh bark of a roebuck sounds from somewhere up the slope.

I walk on for a few paces and spot another deer peeking through the trees at me. It’s a young male that’s just got its first set of thin antlers, probably making it about a year old. Inquisitive, rather than scared, it has a good look at me before ambling slowly off up the hill.

Back to my cuckoo quest. As I walk on, the dense woodland gives way to a more open area, with fields on my right and slopes of bilberry and heather leading to the moor on my left. This looks like good cuckoo territory to me.

I decide to wait on the path and hope my target comes to me. I stand next to a holly tree – and discover, to my surprise, that it’s still sporting clusters of bright red winter berries on this late spring day.

Sounds drift across to me: the coo-coo-coo of a woodpigeon, more squawking pheasants, the sweet song of a willow warbler. 

After about ten minutes, I hear that familiar cuck-oo, cuck-oo again. It seems to be coming from somewhere up the slope, near a dry stone wall where the nature reserve meets the moor. I scan the wall, the trees and the ground through binoculars…without success.

The cuckoo falls silent again and, after waiting in vain for a while, I decide to try a new approach and head for the moor to see if I can get closer to my elusive quarry. After retracing my steps, I’ve just reached the thicker woodland when I become aware of a mocking cuck-oo, cuck-oo. Of course, it’s coming from the place I’ve just left. Time for another U-turn. 

The call gets louder as I approach. Then, at last, I spot the cuckoo. An aerodynamic shape, like a sparrowhawk or kestrel (cuckoos are often misidentified as birds of prey) flies high over my head, then across the fields towards the other side of the valley.

A few seconds later, the bird has vanished, pulling the plug on the cuck-oo, cuck-oo. These days, though, any sighting of one of these increasingly scarce visitors feels like a success.

In the afternoon, I climb onto the moor and meander along the path that looks down at the bilberry and heather slopes of the reserve. I don’t spot any more cuckoos, but I do see plenty of birds of another species that plays a key part in their lives.

Meadow pipits – and other small birds like dunnocks and reed warblers – are the reason why cuckoos are free to skip back to Africa in June, while others are toiling to raise their chicks.

The cuckoo’s penchant for contracting out childcare to unsuspecting “hosts” is almost as well-known as the male bird’s signature call. It’s a ruthless strategy known as brood parasitism. Cuckoos don’t build their own nests. Instead, the female lays between 12 and 22 eggs, each one in a different nest and designed to mimic those of the host species. 

The meadow pipits and other hosts get a raw deal. The female cuckoo turfs out one of the original eggs to make way for her own, then the cuckoo chick hatches quickly and monopolises all the food brought in by its adoptive parents.

As I watch streaky-brown meadow pipits flitting around their nests on the moorland, I wonder if some of them will end up unwittingly nurturing the next generation of cuckoos. 

It’s time to leave Broadhead Clough. As I head out of the reserve down the steep track towards the road, I notice clusters of delicate, pale pink flowers growing in the fields. 

They’re cuckooflowers – so called by our ancestors because they appear at the same time of year as cuckoos arrive here from Africa. It’s a reminder of how deeply embedded these fascinating birds have become in our culture over centuries – and what a tragedy it would be if that familiar cuck-oo, cuck-oo continued to disappear from large swathes of the British countryside.