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THE USEFUL BIRDS 



short jumps, examining every inch of surface in this course 

 for insects. As the observer, watches the bird he will see that 

 it disappears on the other side of the tree, only to reappear 

 in a few seconds on the observer's side, but higher up the 



White-throated Tree-creeper. 



trunk. The"search for insectscauses the bird to continue this 

 staircase movement until it has reached the branching forks, 

 when it flutters down to the base of another tree, and repeats 

 its previous performance. Insects clinging to the tree thus 



