This, the largest in our three woodpeckers, differs from the others with size, but additionally in plumage, voice and habits. From the distinctive laughing refer to it as has many country names, for example 'yaffle'; in some districts it's also the 'rain-bird', and the calls, loudest and most frequently uttered during mild April weather, are taken as 'boding rain'.
Its most un-woodpecker like habit is feeding on the ground, and in all likelihood this source may provide the main issue with its diet, because of not only will it frequent drier ground looking for ants throughout the summer, however it may also be seen probing in damp lawns and pastures at other seasons, eating both earthworms and leatherjackets.
If blackbirds or starlings approach too closely on such occasions, an amazing threat-display may be observed; the woodpecker stiffens within an upright position, elongates its neck for an extraordinary extent, bill pointing upwards, and slowly moves its head laterally.
The somewhat fearsome, snakelike performance, and the sinister appearance of the slightly puffed-out black moustaches, seem very efficient in warning-off possible competitors without the requirement for any more direct action. (It's interesting to notice that a kingfisher reacts to the indignity to be held in the hand with a similar intimidating performance.) The green colour which provides this bird its name is most noticeable on such birds on the ground at close quarters; flying the bright yellow of the rump is exactly what catches the eye.
Since the green woodpecker's alternative mode of feeding causes it to be less based mostly on trees, it's the species most apt to be seen in prolonged flight when disturbed from the ground in open country; it thus affords the best opportunities for noting typical woodpecker flight-a few wing-beats upward, then a shallower plunge downward with closed wings, producing progress inside a series of bouncing undulations.
In several areas there's been a marked decline in amounts of this species, once the commonest woodpecker in England (it had been always scarcer to the northward, occurring sparingly in southern Scotland, and never at all in Ireland).
It might be that its ground-feeding habits had become this kind of established a part of its dietary routine that could not obtain sufficient food during the any period of time of snow-cover in the winter of 1962-63. (It's far less prone to accept the hospitality of the bird-table than the pied woodpecker, although in certain previous snowy winters, one will come regularly to peck at apples positioned on the ground.) Another possibility, because of the supply of much of its food, is the fact that through ants, leatherjackets and earthworms it might have accumulated lethal doses of the insidious farm and garden insecticides of contemporary times.