XXI T. BIRDS 



Chordata (coidiniied) 



Clas^ V. — Arcs (ori'.N, bird) 



As a class, the hii'ds are very \iiiiform in their essential 

 characteristics. There is probabl}' nut a bird in existence 

 that would not be recognized as such on siglil. The birds of 

 the world liave Ix'cn gi'ouped into nineteen tlifi'erent 

 orders, seventeen of which are represented in North America. 

 They are widely distributed and are of very great service to 

 man, althougli their usefulness is j)oorl)' understood and 

 but little appreciated. Notwithstanding the fact that all 

 birds possess feathers, they exhibit a considerable variety 

 of form and habits. Some are flightless and run upon land; 

 some are flightless and live almost entirely in or upon the 

 water; some have very great powers of flight and spend 

 their lives flying over the sea, while others with ecjually 

 strong wings soar higli in the air over laniL Some fish for 

 a living, some come forth at night to kill, some scratch for 

 their food, while others live upon seeds and ^'arious vege- 

 table jiroducts. The study of Ijirds with a field glass and 

 camei'a, not with a gun, is one of the most interesting and 

 enlightening lines of natural histury woi'k. 



ExAMrrn; of thk C'lass — thk K^ncu-ish Sparrow 



Origin and distribution. — This spai'row was introduced 

 into Aiiiei'ica from jiingland ;d)out: l.srtO and for this reason 



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