VARIETY OF ARCHITECTURE 



ing to note that the bird which displays so much energy, 

 zeal, skill, and foresight where the welfare of its family is con- 

 cerned is in its own life an utter Bohemian, living carelessly 

 from day to day and seldom making any provision for the 

 future. Fortunate it is for him, in many cases, that when 

 the cold weather comes and food is scarce, he can fly away to 

 a kinder and more congenial climate, there to remain until 

 the return of summer. 



Birds attach a great deal of importance to the stability of 

 their nests. Those species which have no great skill in 

 building, such as the redstart, the rock dove, and the nut- 

 hatch, plant them firmly on the ground, in a hole in a bank 

 or hollow tree, or within some crevice or cranny of a rock. 

 The more expert architects, on the other hand, often show 

 great daring in their selection of a site, constructing their 

 nests high in a bush or in some tall tree; yet taking care, for 

 their greater security, to place them on the fork of a branch, 

 or even in many cases building around two or three stout twigs, 

 which pass through the walls of the nest and prevent it from 

 being dislodged by the strongest wind. Birds which build in 

 marshy places give the same attention to the security of their 

 foundations, and anchor their nests to the surrounding reeds 

 by cables, as it were, of flexible rushes. 



The walls of different nests vary in thickness and strength 

 not only in proportion to the weight of the brood they are 

 destined to contain, but also with the number, position, or 

 firmness of the points of support. Thus the side of a nest 

 which is in contact with the trunk of a tree, a wall, or a 

 rock is commonly very thin and may in some part be want- 

 ing altogether; while the side which projects into space 

 without any direct support is necessarily made much thicker 

 and stronger. 



Most birds bind together more firmly the materials which 



