Harbingers of spring are many and varied and no doubt we all have a favourite which means something special to us.

Snowdrops; primroses; celandine early on perhaps followed by bluebells and blossom which comprise the floral aspect while brimstone, orange tip and small tortoiseshell butterflies emerge on sunny days.

Maybe the first swallow or swift delight us and of course birdsong becomes prominent with blackbird, songthrush and migrant species such as chiffchaff, which sings its own name and the liquid fruity song of blackcaps that are super-abundant this spring.

However, there is one ingredient of the springtime mix that is sadly missing and the is the iconic voice of the cuckoo, surely everyones choice of favourite harbinger and indeed, the epitome of spring's awakening.

The bird has declined by two thirds in twenty years. Reasons for its scarcity are unclear but one possibility is associated with its overwintering grounds in Africa.

Another factor may be related to the cuckoo's diet which consists of hairy caterpillars (see picture) known as 'wooly bears' when we were children and mainly the larvae of the garden tiger moth that has suffered a massive decline, along with moths in general.

Pesticide spraying and grubbing out of hedgerows are probably to blame too.

In my former Northamptonshire cuckoo hotspot the bird has not been heard for three years.

It would be interesting to know if any readers have heard a cuckoo this spring?