This is the time of year when the morning dog walk in Sefton Park is accompanied by the loud drumming of the Great Spotted Woodpecker. It’s a handsome bird when you catch a glimpse of it, either clinging to a tree trunk or flying from tree to tree in a flash of black, white and red. This morning I heard a commotion in the branches above me and saw something quite remarkable.
Since the 1950’s these birds have become increasingly common in parks and gardens throughout Britain. Once you have spotted one, they are easy to identify, being predominantly black and white, with a patch of red at the base of the body. You can distinguish males from females because the adult male has a small red patch on its head (juvenile birds exhibit a larger red patch that later disappears). But in spring their presence is usually betrayed by the sound of their drumming.
Although many people assume that they’re hearing the sound of a nest being drilled, that may not be the case, at least early in the season. In February, before the onset of the breeding season, the male woodpecker drums to signal for a mate. Selecting a hollow tree or dead branch with promising resonant qualities, he taps rapidly on the bark with his bill, making a rattle-like drum roll that is startlingly loud and carries for a considerable distance through woodland. Males not only drum in order to attract a mate – throughout the year they will continue to drum to proclaim their territory. Each male has his own drumming sequence and stops to listen to the replies of males nearby.
The drumming’ is the sound the birds make as they hammer their hard bills against the trunk of a tree. I’ve often wondered how the bird can do this repeatedly without doing itself serious brain damage. Here’s the answer, given on the British Trust for Ornithology website:
Hitting a solid tree with your beak so hard that splinters fly ought to cause the brain to rotate in the way that causes concussion in Man. Not a bit of it. The evolution of the bird’s drilling equipment has provided very sophisticated shock absorbing adaptations involving the way that the bird’s beak joins the skull. The stresses are transmitted directly towards the centre of the brain and do not cause the knockout swirl.
The beak is used like a combined hammer and chisel to drill into trees and branches and carve out deep nest holes. When woodpeckers hammer into wood to get at grubs they also have another anatomical adaptation designed to help them feed. The roots of their tongues are coiled round the back of their skulls and can be extended a prodigious distance to harpoon insect larvae in their tunnels.
Once a couple have paired off, the nesting hole, neat and round, is bored in soft or decaying wood horizontally for a few inches, then perpendicularly down. At the bottom of a shaft, usually from six to twelve inches in depth, a small chamber is excavated and lined with wood chips. The female lays up to seven glossy-white eggs in the dark chamber, each parent taking turns to incubate the clutch and later feed the greyish, red-capped fledglings. The young leave after three weeks. The nest hole is rarely used again, though other holes are often bored in the same tree.
What I saw this morning, alerted by a commotion in the branches above, was the sight of two males skirmishing outside a freshly-bored hole. I stood and watched for several minutes as they went at it with a fair amount of ferocity. I assume that what I was seeing was one male attempting to take over the freshly-chiselled hole of the other.
Woodpecker is rubber-necked
But has a nose of steel.
He bangs his head against the wall
And cannot even feel.
When Woodpecker’s jack-hammer head
Starts up its dreadful din
Knocking the dead bough double dead
How do his eyes stay in?
Pity the poor dead oak that cries
In terrors and in pains.
But pity more Woodpecker’s eyes
And bouncing rubber brains.
– Ted Hughes, from Under the North Star, 1981