ONE seasonal landmark for me is when I first hear the distinctive call of the cuckoo.

It was April 16 this year when I heard the call which gives the cuckoo its name,ringing out across Hartlebury Common.

This was, as with most things this year rather early, as it is more commonly first heard in the area during early May.

Through the winter months the cuckoo spends its time just south of the equator, in and around scrublands.

During spring it flies north to a host of European countries, including Britain where it mates and looks for a host for its brood.

Cuckoos are notorious parasites.

They search out the nests of other species of birds then, when the parents of the clutch of eggs contained within the nest are not paying too much attention, the female cuckoo lays one of her eggs in the nest. To give their eggs an unfair advantage; cuckoos have the ability to partially incubate them within their bodies.

This means their eggs usually hatch prior to the rightful eggs of the nest. Once the young cuckoo has hatched, it spends about a day gathering its strength before, with a relentless determination ousting the rightful eggs from the nest. Even if the cuckoo is not fortunate enough to hatch first it still rids the nest of any competition by smothering the other young. The cuckoo chick then tricks the nest builders into caring for it and feeding it as it grows.

Towards the end of the six weeks it takes the young cuckoo to develop enough to leave the nest, it can grow to a size which dwarfs the cuckoo's surrogate parents.

This can put a great strain on them, as the young birds constantly demand food. Their cries are so raucous they give away the location of a cuckoo's nest from some distance.

Cuckoos can invade the nests of a large number of different bird species, but individual birds tend to target the nests of just one host species.

Each cuckoo can lay up to 25 eggs in a season.

It is easy to feel pity for the luckless host bird. It is worth taking a moment to consider the evolutionary guile of the cuckoo.

It is also worth bearing in mind that some of the cuckoo's victims are not exactly blameless when it comes to nest stealing.

Sparrows for instance, when finding an attractive swallow's nest, turf the swallow eggs or young out and take it over for themselves.