BORING THE NEST. 71 



beginning at the top branch of a dead tree, tear off 

 the bark to an extent of twenty or thirty feet in 

 the course of a few hours." These birds pay 

 great attention to the situation of the tree they 

 propose to excavate, and to the inclination of its 

 trunk, so as to ensure the seclusion of their nest, 

 and to prevent the influx of rain-water. The 

 hole is generally bored horizontally under the 

 junction of a large branch with the trunk, for a 

 few inches, then directly downwards, sometimes 

 even to the depth of three feet. Both birds work 

 hard at this task, one waiting outside to rest, while 

 the other, lost to view, is working away within. 

 By this equal distribution of labour, their task, 

 difficult as it often is, from the nature of the 

 material, is materially lightened and helped for- 

 ward. 



It is interesting to find birds employing the 

 same instrument, the bill, in the manner of a 

 mason's implement. The house martin makes a 

 most ingenious use of this unlikely tool, so to 

 speak, in the construction of its loamy dwelling. 

 Collecting the materials in the manner we have 

 before described, it builds the foundations of 

 its abode while clinging against the perpen- 



