Have you heard the cuckoo yet? Yes, they’re back and singing along the river valley. Their sound is so distinctive and unusual that we name the bird after its call.

The mating call of the male bird has inspired music, clocks, folk-lore and letters to The Times. And from its simple, two-note song we give the cuckoo the rather fond description of ‘silly’ – but silly, this bird is definitely not.

It is clever, calculating and, to our sensibilities, cruel. And it is a survivor – now more than ever. Due to a near 65 per cent decline in its numbers since the 1980s the cuckoo is on the ‘Red List’ of Birds of Conservation Concern.

Cuckoos have an average life span of five years, but one celebrity cuckoo called Colin, has been turning up on Thursley Common in Surrey for at least the last seven years to the delight of the twitcher paparazzi.

Once the cuckoos have made the journey from central Africa, crossed the Sahara, avoided droughts and evaded hunters, they find a suitable summer habitat and good food supply (moth caterpillars) in areas such as the meadows and wetlands along the Great Ouse.

The cuckoos time their arrival to fit with the breeding times of these unsuspecting little birds who will become the step-parents of ever-hungry fledgling cuckoos. The female cuckoo cunningly drives the host bird away from its nest, often by mimicking the call of the sparrowhawk.

She can lay up to 25 eggs, one at a time, in various nests. The cuckoo egg hatches earlier than the host bird’s eggs so the young cuckoo is already advantaged. It mimics the calls of the chicks around it to ensure it will be fed and then, as it grows quickly, it gradually pushes all the host’s young out of the nest to make sure it receives all the food.

Exactly why cuckoos travel such a distance from the Congo just to propagate their species is not fully understood. Once their eggs are laid the parent cuckoos (if they can be called that) do not wait to see their young; they fly back to Africa in July after barely four months here.

If you can capture an Ouse Valley cuckoo with your camera this spring send it to the Great Ouse Valley Trust and we will publish the best on our website.

The Great Ouse Valley Trust promotes for public benefit the conservation, restoration and enjoyment of the landscape, wildlife and heritage of the Great Ouse Valley and environs in the county of Cambridgeshire. Visit: www.greatousevalleytrust.org.uk.