GENERAL HABITS 179 



into fairly natural orders ; traced the distribution 

 of birds over the world, and then discussed the 

 laws of their dispersal and migration. The most 

 characteristic habits and functions of Birds may 

 now fittingly help their story onwards. 



Of course it would be quite impossible to give 

 even the barest resume of the habits, infinite in 

 variety, of nearly twelve thousand species of 

 birds. On the other hand we may, at least, be 

 successful in describing some of the more charac- 

 teristic habits possessed by most birds in common, 

 together with a few of the more remarkable pecu- 

 liarities of the class. These naturally group 

 themselves into various classes of phenomena, 

 among which we may mention Flight, Terrestrial 

 and Aquatic Motion, Social, Gregarious, or Soli- 

 tary Instincts, Food and the many methods of 

 procuring it, Mimicry, Protective Colours and 

 Resemblances, and, lastly, the very difficult 

 problems of Variation and Dimorphism. 



We will first devote a short space to that func- 

 tion of the wings termed Flight, together with 

 certain aerial habits of birds. Flight may be said 

 to be nearly universal among birds ; it is one of 

 their most remarkable characteristics, their name 

 being almost synonymous with an aerial exist- 

 ence. There are, comparatively speaking, very few 



