I 2O VERTEBRATES I BIRDS. 



all individuals of a species build alike, and, in a given 

 locality, of the same kinds of material. Their skill and 

 industry are in the highest degree remarkable, but can- 

 not be dwelt upon here. Their ability to anticipate 

 atmospheric changes is truly wonderful, and caused the 

 ancients to attribute to them the power of divination. 

 Cuvier says that on this faculty depends the instinct 

 which acts upon birds of passage, prompting them to 

 seek the sunny climes on the approach of winter, and 

 their old homes as summer comes again. 



The longevity of birds is regarded as about ten times 

 as great as the period which they require to come to 

 maturity or full growth. Domestic fowls live to the age 

 of twenty years ; parrots, thirty years ; geese, fifty ; while 

 swans, ravens, and eagles are said to live a century. 



The Class of Birds comprises ten to twelve thousand 

 species, and is divided into seven Orders * : the Order of 

 Raptores or Raveners, the Order of Scansores or Climb- 

 ers, the Order of Insessores or Perchers, the Order of 

 Rasores or Scratchers, the Order of Cursores or Runners, 

 the Order of Grallatores or Waders, and the Order of 

 Natatores or Swimmers. 



SUB-SECTION I. 



THE ORDER OF RAPTORES, OR BIRDS OF PREY. 



THE Order of Raptores comprises all Birds of Prey, or 

 those which, with few exceptions, pursue and capture 

 birds and other animals for food. They are mostly of 



* Bonaparte and some others divide the Class of Birds into two Sub- 

 classes, called ALTRICES and PRECOCES, the former comprising those whose 

 young hatch in a very feeble condition, and require to be fed for a consider- 

 able time from the bill of the parent, and the latter those whose young are 

 able to run about and pick up food for themselves as soon as hatched. 

 Each of these Sub-classes is divided into orders which stand in parallel 

 series. 



