33 



(D) Description of the Nesting -boxes. 



Whoever has had an opportunity, like the author, of comparing the 

 sections of woodpecker holes with these artificial boxes will be astonished 

 at their similarity. He will almost be inclined to think that the 

 woodpeckers modelled their holes on those of Baron von Berlepsch. 

 Compare the accompanying illustrations of longitudinal sections of 



B. 



LONGITUDINAL SECTIONS OF 



A. Great Spotted Woodpecker's hole. 

 B. Berlepsch's Nesting-Box, size B. 

 (One-eighth natural size.) 



natural and artificial holes. A closer description of the boxes, the 

 different measurements, the position of the opening, the boring and 

 arrangement of the interior, can be given more clearly by the following 

 diagram accompanied by a scale than would be possible by a verbal 



