144 THE BIRDS OF SHERWOOD FOREST. 



odd, festooning flight from tree to tree, but not invariably 

 so, as I have heard it both when clinging to a tree and 

 when on the ground. The latter situation is only fre- 

 quented where there are anthills, when it willingly leaves 

 its strongholds the trees, to search for its favourite 

 food. 



Its motions on the trees, for which it is so admirably 

 fitted, are well worth watching. I never saw it by any 

 chance perch on the upper side of a bough, but it is 

 fond of clinging to the under side, where during the day 

 insects chiefly congregate. It is on the perpendicular 

 trunk, however, that it is most at home. Commencing 

 at the base it pursues a spiral course to the top, prying 

 into every chink and crevice, tapping here and there 

 with vigorous and rapid strokes to alarm its insect prey. 



I have remarked previously that nearly all the old 

 oaks in the forest have suffered the loss of their tops by 

 the agency of wind and lightning, aided by natural 

 decay. Sometimes you may see the upper portion of 

 one of these venerable trunks quite denuded of its bark, 

 and riven with many fissures, though the tree is all the 

 while in vigorous growth. On some of these I have 

 often noticed the green woodpecker practise a singular 

 feat. Placing its bill in one of the long cracks I have 

 mentioned, it produces, by an exceedingly rapid vibra- 

 tory motion, a loud crashing noise, as if the tree was 

 violently rent from top to bottom. I have heard it 

 when the sound was so loud and sudden that the woods 

 rang again. For a long time I was at a loss to know 

 how it was produced, but I one day witnessed the pro- 

 cess, and have seen it several times since. It would 

 effectually rouse up all the insects, for it seemed as if the 

 tree quivered from top to bottom. 



