Great spotted woodpecker. Image by Alan Moffet

Now's a great time of year to take a walk in the woods. Trees are coming into leaf, blossom's busting out, there are lots of birds singing and nests being built. Spring's here - hooray!

The early part of spring is also your only chance to hear something rather special. This is the time when woodpeckers - both males and females - are 'drumming'. They don't sing like most birds, but a quick 'drum roll' is a good substitute to tell rivals who lives here. Choosing a rotten, hollow branch means the sound is amplified and can be heard a long way away.

How does a bird which bashes into a lump of wood repeatedly avoid damaging its brain? The answer lies within. A specially-shaped hinge between the front of skull and beak, combined with a shock-absorbing muscle, protects the bird's brain from the vibration. 

Because the woodpecker's head moves in a straight line, its brain is protected from damage. The bird's relatively small head means it can get away with the immense impact when the beak hits the bark - at a force of more than 1,000 times gravity! 

There are three species of woodpecker which breed in the UK: great spotted, lesser spotted and green. The great spotted woodpecker is the one you're most likely to hear in most parts of the UK (they've even colonised Ireland in recent years). 

Lesser spotted woodpeckers are now pretty scarce in much of the country (we're working to find out why), and green woodpeckers rarely 'drum', preferring a loud, laughing call described as a 'yaffle' - Professor Yaffle from Bagpuss was a green woodpecker.

You can see and hear woodpeckers on lots of our nature reserves. If you're out and about, let me know if you hear any drummers in the woods!