OUR FEATHERED ENGINEERS. 77 



with bill and claws, the latter being exceedingly 

 sharp. In working, the birds throw the loose soil 

 out behind them in an almost continual stream. 

 Other miners are also found among the sea-birds, 

 especially the Shearwaters. 



4. Wood Cutters. In the British Islands the 

 birds falling under this category are few ; but in 

 the tropics there are a great many species, espe- 

 cially in the Picarian order of birds, which cut 

 into wood for the purpose of making a nest. 

 With us, the Woodpeckers are the most typical 

 species, and are birds singularly well adapted by 

 nature for cutting into timber, being armed with 

 long, chisel-shaped beaks exceptionally strong and 

 powerful. All the British species carry on their 

 operations in a similar manner. Take, for in- 

 stance, the Green Woodpecker. In spring this 

 handsome bird selects a branch or portion of the 

 trunk usually one which is more or less decayed 

 and bores at first horizontally for a few inches, 

 then the shaft is sunk in a perpendicular direction 

 for a foot or more, the bottom of which being 

 enlarged into a chamber, where the eggs are laid 

 on the powdered wood without any other nest. 

 Some of these Woodpeckers' holes are marvellous 

 pieces of handiwork, beautifully smooth and round, 

 and appearing as though they had been carefully 

 cut out with a small gouge. The bill is used 

 almost like a pickaxe, and every bit of detached 

 wood is carried and dropped outside, where the 

 accumulation below the tree often betrays the 



