Woodpeckers (Picidae family): Drummers of the treetops.
IT'S A NEAR UNMISTAKABLE SOUND, and one that any countryside rambler will be well acquainted with whilst out on a springtime walk in the environs of a broad leaved, adequately wooded area. The resonant and evocative staccato drumming of woodpeckers echoing through the freshly-budded treetops, bidding to mark out their breeding territories in readiness for the hectic season to come, is an inexorable hint at warmer times ahead and the thought of lengthening days as winter is slowly bid farewell.
Even early in the season, when the woodland canopy is yet to develop, it can be difficult to pinpoint precisely the fountainhead of this drumming as you busily scan the upper branches for a brief glimpse of a thrush size bird, spiralling a path up and around its arboreal soundboard. In Norfolk, as is the case in most of southern Britain, it is perfectly feasible to encounter any one of the three species of woodpecker native to the British Isles (all belonging to the family of birds know as Picidae), two of which -- the great spotted (Dendrocopos major) and green woodpecker (Picus viridis) -- you are much more likely to happen upon than the smaller and more elusive sparrow-sized lesser spotted woodpecker (Dendrocopos minor): the former are generally more numerous than the latter, a glimpse of which to most birdwatchers is a red-letter-day sighting.
The lifestyles of the county's three woodpeckers follow a very similar pattern, yet it is worth knowing the individual characteristics of each species to improve your chances of locating them. One of the most distinguishing features of all three is their flight pattern when crossing open areas (less common with D.minor), where an undulating aerial navigation is interspersed with bouts of flapping and gliding as the birds bound along to their chosen destination. Although all three species are known to use drumming as a means of communication (the act of whacking one's head against a decaying branch or, on occasion, corrugated roofing), the green woodpecker rarely does, preferring to vocalise with a descending, laughing "yah-yah-yah-yah" call to declare its whereabouts (giving rise to the rural moniker of "yaffle".) The pied woodpeckers are the real drummers and their sound can be distinguished in a subtle way: the larger bird drums for under one-second at 8 - 10 whacks-per-second, the smaller creature a faster, longer but softer burst of 12 - 15 whacks-per-second, lasting twice the duration of the former.
The act of drumming is not the only time these avians beat-up on trees, for they need to eat and will use their chisel like bills in a different manner, systematically chipping and twisting at dead branches to extort the grubs of wood boring beetles and moths concealed beneath the bark, utilising an extraordinarily long, mucus coated, barb tipped tongue that glues or impales their helpless quarry with little effort. This sounds easy enough, but how do you gain enough purchase on an horizontal or vertical surface to impart the necessary force to split wood?: it's simple, by using specialist equipment in the form of super-stiffened tail feathers that act as a prop against the tree's trunk -- in much the same way a country gent would rest on his shooting stick -- and feet with a two-by-two toe configuration (referred to as zygodactlyous) that are armed with crampon-like claws, the woodpeckers are as adept at climbing as they are at flying. If the birds can't find the grubs they're after in the treetops, supplementary fair in the form of fruit, nuts and nestlings from other bird's nests -- particularly titmice - will suffice: they will even make apiculturists lives a misery by raiding beehives to get at the juicy larva within.
There's no doubt that early spring is the best time to catch-up with any of this Picidae tripartite, when they will be more conspicuous without the cover of leaves to conceal their movements that become far more secretive when eggs and young are in the nest, which is usually from late April through to the end of June. To locate the elusive lesser spotted woodpecker, a visit to alder dominated woodland is likely to improve your chances of a sighting, or even an old orchard, where they will choose to nest beneath a sickly branch, up to twenty-meters above the ground. Its larger cousins are less evasive, the great spotted woodpecker preferring denser, unbroken stands of woodland and adjoining spinneys where a sharp "chee-kip" note will give its presence away. Look out for the yaffle in open pastures and parkland, for once they get into the cover of woodland their citrus and lime suffused plumage makes them very difficult to spot.
To avoid the mind-numbing concussion associated with head-butting hard objects, the woodpeckers have evolved a shock-absorbing growth of cartilage between the base of their bills and skull, which in addition to bristle covered nostrils acting as dust filters allows them to beat into submission the of the hardest of woods (including telegraph poles) without the slightest hint of neuralgia.
...armed with crampon-like claws, the woodpeckers are as adept at climbing as they are at flying...
Crown feathers worn and jaded after weeks of non-stop nesting duties, an adult green woodpecker delivers another morsel of food to its hidden offspring. Unbelievably, up to six chicks may be crammed within the tree trunk's cavity.
Days, maybe only hours away from leaving its nesting cavity for the first time, a young woodpecker calls continuously to the parent birds for more food. Gradually, the deliveries are halted, forcing the chick into its maiden flight.
Intriguingly, the yaffle is just as happy to feed on the ground, particularly in arid areas where the predominance of sheep and rabbit grazing has left a short turf and habitat ideally suited to their favourite food: the wood ant.