Ill VARIABILITY OF SPECIES IN A STATE OF NATURE 51 



mencing with the outer one. As an example of the irregular 

 variation constantly met with, the following occurred among 

 twenty-five specimens of Dendrseca coi'onata. Numbers 

 bracketed imply that the corresponding feathers were of 

 equal length.^ 



Eelative Lengths of Primary Wing Feathers of 

 Dendr^ca coronata. 



Here we have five very distinct proportionate lengths of 

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

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

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

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

 carried to scores of others with 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 gi-eat amount of individual variability in the 

 markings of the same species. Birds having the plumage 

 varied -with streaks and spots differ exceedingly in diff"erent 

 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 



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



