WOODPECKER: taking the knocks - and giving a few back

THE drum of beak on wood often announces the presence of a woodpecker long before its distinctive shape is spotted flitting from tree to tree.

As with all woodpeckers, shock absorbers at the front of the skull enable our three native species to drill holes in trees without knocking themselves cold.

Their beaks, too, are extra strong and sharp so they can comfortably excavate nest sites or hack away in pursuit of food.

Prey is usually insects or grubs with woodpeckers' long darting tongues covered in sticky saliva and bristles to increase hunting success.

Stiff tail feathers give woodpeckers additional support and they cling to the rounded trunks of trees with 'zygodactylous' feet - two toes on each foot pointing forward, the other two backward.

As well as attacking dead or dying trees in the hunt for food, the Great Spotted woodpecker drums noisily to establish territory.

Both sexes strike resonant branches as much as 15 times per second so those shock absorbers are vital.

A thrush-sized bird, the Great Spotted has distinctive black, white and red colouring. It is also the most common British woodpecker, therefore much more likely to be seen.

The Green woodpecker - our biggest and most beautiful species - is about the size of a pigeon and boasts a dazzling crimson crown atop lustrous green and yellow plumage.

It is also extremely shy and will dart away into cover at the slightest disturbance. Often, after that, only its curious laughter-like "yaffle" cry betrays its whereabouts.

The sparrow-sized Lesser Spotted woodpecker, meanwhile, is actually the rarest and quietest of the trio.

It looks like a smaller version of the Great Spotted and spends much of its life hidden from view, feeding in the topmost branches of the forest. According to the British Trust for Ornithology, the Lesser Spotted is also the only species showing a consistent decline.

Surprisingly, perhaps, both Great Spotted and Green woodpeckers appear to be doing well.

Great Spotted numbers rose rapidly in the 1970s, levelled off, and are currently stable - still an achievement when so many other species are plummeting to oblivion.

But Green woodpeckers are enjoying even greater success.

"Green woodpecker populations have increased steadily since 1966, except for a period of stability or shallow decline centred on the late 1970s," revealed a BTO spokesman.

No-one knows why these two species are doing so well but experts suspect both thrive in man-made commercial forests, especially when dead or dying trees are left to provide food and nest sites.

So at least some woodland birds are taking the knocks - and giving a few back.