Woodland Drummer Birds
You can tell a spotted woodpecker by its frenzied activity even before you come close enough to recognise its brilliant colouring. Its persistent drumming against wood to attract a mate and proclaim territory is unique among British birds.
The great spotted woodpecker is both the most numerous and widespread of our woodpeckers, occurring in almost all areas where there are suitable trees. Strangely enough, the great spotted shares with its relatives a complete, unexpected, difficult-to-explain absence from the whole of Ireland. Even though there is abundant suitable woodland. There have been sightings in Ireland, but these seem to be of Continental migrants blown off-course in autumn, and none has stayed to breed. The lesser spotted woodpecker is much less common than the great. It does, however, share many characteristics of the great, and has all the same adaptations, though they are reduced in scale.
The great spotted woodpecker prefers stands of timber where at least some of the trees are mature, usually with a few dead or dying branches. It lives in both deciduous and coniferous woodlands, or a mixture of the two, but is scarcer in closely planted coniferous plantations without old or decaying trees. Where good hedgerows are still common, it penetrates deep into agricultural land, feeding and nesting in the tall trees of the hedge, or in spinneys and copses linked by the hedgerow network. It is unusual to find great spotted woodpeckers in isolated clumps of trees.
The magnificent old trees of parkland offer an ideal habitat, and through parks the great spotted woodpecker sometimes penetrates into urban areas. It is a common species of large old gardens, with big trees, that meet the surrounding countryside.
With its pied plumage and scarlet patches, the great spotted woodpecker is a conspicuous bird. Its normal year-round call, a harsh and far-carrying ‘tchack’, or its staccato breeding-season drumming, quickly draw attention to its presence. Its deeply undulating method of flight, too, is conspicuous and characteristic, consisting of a few flaps of the rounded wings, followed by a deep swooping glide, before the next series of flaps helps it gain height again.
The wings are boldly barred black and white, with a striking white oval patch on each wing near the body-a feature lacking in the lesser spotted woodpecker. The back is plain black (again, different from the lesser spotted, where the white bars cross the back as well), and the underparts are white save for a bright scarlet patch beneath the tail of both sexes. In addition, the male has a small block of scarlet feathers on the nape of his otherwise black crown.
Woodpeckers perch, or rather cling, to the sides of tree trunks and branches in a characteristic head-up position developed in the course of evolution as the tail feathers have become specially strengthened and inflexible, serving as a third leg, or prop, to use in climbing in much the same way as we balance on a shooting-stick. This adaptation assists a particularly powerful grip. Woodpecker legs are short but muscular, with strong toes tipped with long, sharp claws which give an effective hold even on the smoothest-barked trees such as beech. Unusually for a bird, the toes are arranged with two pointing forwards and two back, (a condition called zygodactyly), which gives optimum performance on a vertical surface. Thus woodpeckers move vertically or often in a spiral up the trunk, and occasionally laterally. When they have finished searching for food on one tree, they swoop off to the base of another tree or branch and begin to ascend once again.
The most obvious wood-pecking adaptation is, of course, the beak. In the great spotted woodpecker this is relatively short, stout and sharp, with a squared-off end like a small chisel-an appropriate simile: rather than bludgeoning its way into the wood by sheer power, the woodpecker uses its beak as a combination of hammer and chisel, inserting the tip into the crack it has made and using its powerful neck muscles to twist the beak and prize off flakes of wood.
One obvious question relating to wood-peckers is: why don’t they get splitting head-aches? The answer lies partly in the robust bone structure of the skull, especially in front of the brain, and partly in a layer of shock-absorbing cartilaginous material that forms a cushion between the bones within the beak and the rest of the skull.
The diet of the great spotted woodpecker is varied, and includes seeds, fruit and nuts. Nuts are often removed to a well-used cleft in a favourite piece of bark, and hammered open while they are held in position in this natural vice. Insects and larvae are another important food item. During winter these are often found sheltering under easily lifted flakes of bark; the great spotted woodpecker is also a specialist at extracting wood-boring larvae that have tunnelled into trees. The bird senses the approximate location of the grub, perhaps hearing minute sounds of movement or chewing. After a few swift pecks an opening is hacked into the tunnel, and then the woodpecker’s enormously long tongue comes into play. In the case of the great spotted, the tongue can be extended for a couple of inches up the tunnel. The luckless grub is harpooned by the sharp, barbed horny tip of the bird’s tongue, and dragged out to be eaten.
At rest the phenomenally long tongue is far too bulky to lie in the floor of the bird’s mouth: a thickened tube runs out of the lower jaw, backwards beneath the hidden ears and then up the back of the head to the top of the skull. It is here that the tongue is retracted when it is not in use.
The natural all-year-round diet is augmented at various times by rather surprising items. The great spotted woodpecker has a marked taste for the nestlings of other birds. And is adept at catching them. As they grow, the nestlings of most hole-nesting birds, such as tits, alerted by the shadow of their parent falling across the hole, jump up to the nest hole entrance. Woodpeckers have capitalised on this: as their shadow falls across the hole a young tit jumps up to be the first to be fed, and the woodpecker reaches in and grabs it, dragging it out to hack up and eat on a more suitable perch. Sometimes woodpeckers learn to associate this food supply with nestboxes put up for tits, and they chisel their way through the back of the box to get at the eggs or young. In rural and suburban areas from late summer through the winter great spotted woodpeckers are regular visitors to garden bird tables. They come particularly for fat, suet and peanuts. Even if the peanuts (or .the fat) are suspended on a string, the woodpecker quickly cuts through it with its sharp beak, dropping the food to the ground where it is easier to eat.
Great spotted woodpeckers excavate their nesting chambers in the trunk or a stout branch of a tree. The nest is usually at least 3m (10ft) above ground. The entrance hole is circular and about 6cm (2in) in diameter-slightly smaller and less round with the green woodpecker and rather larger with the lesser spotted. A short horizontal tunnel leads to the pear-shaped nest shaft which is 25-30cm (10-12in) deep.
Each clutch is generally six, or fewer, beautifully spherical white eggs that are incubated by both parents in turns for 16-17 days. When they hatch, the youngsters are naked and noisy, and particularly ugly and reptilian-looking for small birds. They fledge in about three weeks, depending on the weather. There is normally one brood each summer.
Drumming for a mate
The male advertises for a mate and later indicates the boundaries of his territory by drumming on an appropriately resonant, often dead, piece of branch. On occasion woodpeckers seek special effects by drumming on a corrugated iron roof. For many years controversy raged over how the noise was produced. Many skilled ornithologists argued that they could see that it was made vocally, much as we can ‘roll rs’ with our tongues curled. The issue was only settled in the 1930s by embedding microphones in regularly drummed branches, which showed that a rapid succession of physical taps by the beak against the tree caused the noise.
Compared with the short and powerful bursts of drumming of the great spotted, the lesser spotted woodpecker drums at a noticeably higher pitch and in drum-rolls lasting twice as long.
The lesser spotted woodpecker shares the pied, barred plumage of the great, although it lacks the scarlet beneath the tail. It is the smallest European woodpecker. The circular nest hole is only about 4cm (1-1/2n) wide and the nest is usually situated on the underside of the dead branch. There are normally four to six white eggs, and incubation and fledging take much the same time as in the larger bird. The eggs are incubated by both the male and the female parent, and both birds also feed the nestlings.
The lesser lives in similar habitats to the great spotted, although it penetrates less into agricultural and urban surroundings other than in old orchards which it particularly favours. It is nowhere very numerous. Old county reports and Victorian bird books. However, indicate that in the latter half of the last century the lesser spotted was the commoner, the greater spotted the rarer woodpecker. It would be fascinating to know the reasons for the change. Perhaps they are similar to the causes of the recent increase in lesser spotted woodpecker numbers. For some reason they seem to have profited particularly from the Dutch elm disease outbreak, feeding off the numerous insects that live beneath the dead bark and nesting in the rotting wood: at least some small benefit from the disease.