INSTINCT AND INTELLIGENCE. 



75. Sometimes, however, a much more complicated and arti- 

 ficial structure is produced. The nest of the baya, a little bird 

 of India, resembling the bullfinch, (fig. 20,) has the form of a 

 ilask, and is suspended from some branch which is so flexible 

 that neither serpents, monkeys, nor squirrels can approach it. 

 But still more effectually to secure the safety of their young, the 

 mother places the door of the nest at the bottom, where it can 

 only be reached by flying. This habitation would be liable to 

 fall to pieces if it were formed of straws or filaments laid hori- 

 zontally ; it is, therefore, constructed with admirable skill of 

 blades or filaments arranged longitudinally. Internally it is 

 divided into several chambers, the principal of which is occupied 

 by the mother sitting on her eggs ; in another the father of the 

 family is accommodated, who is assiduous in his attentions to 

 his companion, and while she fulfils with exemplary tenderness 

 her maternal duties he amuses her with his song. 



76. Another oriental bird, called the sylvia sutoria, or sewing 

 wood-bird, builds a nest equally curious. This little creature, 



collecting cotton from the cotton-tree, spins it 

 with its bill and claws into threads, with 

 which it sews leaves round its nest, so as to 

 conceal its young from their enemies (fig. 21). 



77. Different species of animals are go- 

 verned by social instincts which vary, but arc 

 always conducive either to the preservation 

 or the well-being of the individual, or to the 

 continuance of the race. When the food by 

 which they arc nourished is not so abundant 

 as to support any considerable numbers in the 

 same locality which is generally the case 

 with the larger species of carnivorous animals 

 they are endowed with an antisocial instinct, 

 and not only lead a solitary life, but in many 

 eases will not surt'er any animal of their own 

 species to remain in their neighbourhood. 



78. Occasionally, however, the operation of 

 this instinct is suspended. This takes place 

 either when a scarcity of subsistence forces 

 them to seek for food in places where they 

 would be liable to attacks, against which their 

 individual force would be insufficient for de- 

 fence, or where some large flocks of animals of 



the sort on which they prey happen to come into their neigh- 

 bourhood. In such cases they assemble by common consent in 

 considerable numbers, and attack their prey in a body. Thus 

 148 



Fig. 21. Nest of tlic 

 Sylvia Sutoria. 



