CLASSIFICATION 



Although birds have been studied more than any other class of animals, 

 authorities on classification are still widely at variance in their views as 

 to the proper arrangement of orders, families, genera and species. The 

 difficulty arises from the fact that birds, although so closely related to 

 reptiles that Huxley proposed to unite them in the same class, have never- 

 theless been so modified in details of superficial structure and in color, 

 that there has been a continual temptation to raise groups into higher 

 positions than correspond to those of equal value in other branches of the 

 animal kingdom. At the same time the differentiation of the various 

 portions of avian anatomy has reached such a high development, on account 

 of the bird's freedom of movement and adaptability to surroundings, that 

 it is sometimes impossible to decide whether a given structure or its absence 

 is due to real relationship or to a parallel development in unrelated forms. 

 Assuming that the different systems of classification are intended to repre- 

 sent, as they should, the real relationship of the different species, it will 

 be evident from a survey of the arrangement of the different orders of 

 birds found in New York State, in the three systems which are best known 

 in America at the present time, how far we are from a complete knowledge 

 or agreement on this subject. It must be borne in mind, however, that 

 no linear sequence of species such as becomes necessary in book -writing 

 can possibly show the proper relationship of the families and species. An 

 arrangement like the spreading, dividing and subdividing branches of a 

 tree could be made to show much more acctirately their proper relation- 

 ships. When we consider the difficulty of discovering the complete history 

 of the evolution of birds, on account of the wonderful parallel development 

 which has occurred in many orders and families, and the insuperable ob- 

 stacles in the way of a linear arrangement, it will be easy to tmderstand 

 the disagreement of authorities on classification. It is certain that a 

 more correct arrangement could be adopted than the classification current 



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