'How I finally managed to catch the cuckoo's famous trick after 30 years'

These small, delicate birds had been tricked into thinking the cuckoo was theirs. It’s an ancient parasitic relationship that has long fascinated me.

In fact, my film was a long time in the making. I first attempted it at a nest I found close to my home and gallery here in East Yorkshire some 30 years ago. But back then my equipment was relatively basic.

These days, however, cuckoos are more scarce. Recent dramatic declines in populations mean they are now listed as ‘red list species.

Each year I visit the same set of lakes to film kingfishers, swans and grebes that live on this species-rich body of water and in the spring, I used to hear the distinctive ‘cuck-oo, cuck-oo’ calls of the males, which gives this species its name.

But it’s a sound I hear less and less these days and, for a few years, not at all. Then last year, after a long absence, I heard three. Two males calling ‘cuck-coo’ and a female’s strange, squeaky response.

At these lakes, the cuckoos were specialists in reed warbler eggs. I decided to check for signs and discovered 13 reed warbler nests, but again none had cuckoo eggs inside. But as these young warblers fledged, I decided to resume my quest. I set off for one more round.

This time I entered the lake from an island. Before I had waded a couple of metres, I spotted a warbler nest I hadn’t seen before.

Reluctant to get too close, I reached over with my mobile phone and photographed the nest, hoping to snap a cuckoo egg.

As I brought my phone back to take a look, I couldn’t believe what I saw. Instead of an egg, I had photographed a cuckoo chick, so big it almost filled the nest.

I had yet to set up my cameras when both warbler parents arrived, their beaks stuffed with insects. As the cameras rolled, a warbler arrived with a mouthful of insects and I filmed as it gently proffered them to the chick.

I watched fascinated as further food deliveries arrived. Whenever the warblers approached, the cuckoo chick’s red gape opened wide, and it let out a shrill call for food. Over the weeks, a wide range of insects were delivered. It wasn’t long before the cuckoo chick was so big it struggled to fit into the nest.

As the cuckoo got bigger, its calls for food became more frantic and louder, driving the warblers to work even harder.

Soon the chick was venturing to the rim of the nest. Then one day, as the wind blew through the reeds, I noticed the cuckoo chick peering out over the nest.

The following morning, the cuckoo wasn’t in the nest. I soon found it in a moorhen’s nest at water level.

As the evening came, I grew worried about its safety down there where predators could easily find it, so I popped it back onto the warbler nest. With cuckoo populations so low, I felt compelled to do what I could to help this one survive.

But the next morning it had hopped back out. Again, I found it low down in the reeds. The cuckoo perched there for hours, gobbling up food delivery after food delivery. But then it made a jump for dry land and scrambled up to the island.

Once on the island, the cuckoo started hopping up through the willow branches and when it was a few feet off the ground it settled and cheeped again for food.

The warblers found it straight away and again began to deliver more food. Then the cuckoo chick made its way onto a broken-off stump and here the warblers had nothing to perch on to feed it.

Over the next days the cuckoo fledgling stayed on this island, practising its flying skills. It soon progressed from short jumps between branches to longer flights of a few metres. All the time the warblers brought a seemingly everlasting supply of insects.

Once after attempting a longer flight, the chick crashlanded into the reed bed and slipped into the water. Again, cuckoos are in sharp decline so I helped it back to dry land and soon its flights got stronger and it left the island, flying well.

Watching its halting, first attempts, I was amazed to think that in a few weeks, this bird would soon set off for an epic journey to West Africa, but that’s the magic of nature. And what an amazing experience it was to document this part of its life.

See paintings inspired by Robert E Fuller’s wildlife sightings at his Winter Art Exhibition at his Thixendale art gallery until January 6. www.robertefuller.com