Ill VARIABILITY OF SPECIES IX A STATE OF NATURE 51 



mencing -^dth the outer one. As an example of the irregular 

 variation constantly met with, the following occurred among 

 twenty -five specimens of Dendraeca coronata. Numbers 

 bracketed imply that the corresponding feathers were of 

 equal length.^ 



Eelatrt: Lengths of Prbiary Wing Feathers of 

 dendr.eca coronata. 



Here Ave have five very distinct proportionate lengths of 

 the Aving feathers, any one of which is often thought sufficient 

 to characterise a distinct species of bird ; and though this is 

 rather an extreme case, Mr. Allen assures us that "the com- 

 parison, extended in the table to only a few species, has been 

 carried to scores of others ^yiih. similar results." 



Along with this variation in size and proportions there occurs 

 a large amount of variation in colour and markings. " The 

 difference in intensity of colour between the extremes of a 

 series of fifty or one hundred specimens of any species, collected 

 at a single locality, and nearly at the same season of the year, 

 is often as great as occurs between truly distinct species." But 

 there is also a great amount of indiWdual variability in the 

 markings of the same species. Birds having the plumage 

 varied with streaks and spots differ exceedingly in diflerent 

 individuals of the same species in respect to the size, shape, 

 and number of these marks, and in the general aspect of the 

 plumage resulting from such variations. "In the common 



1 See Winter Birds of Florida, p. 206, Table F. 



