No. 501] THE SPECIES QUESTION 5 ( )7 



to some extent the coloration, and especially the relative 

 size and massiveness of the bill. The extremes of varia- 

 tion in the latter are enormous for the size of the bird. 

 As such individuals occur, however, more or less gen- 

 erally throughout the exceptionally wide (almost con- 

 tinental) range of the species, and are thus not char- 

 acteristic of any particular locality or region, and also 

 are everywhere associated with birds of intermediate 

 characters, these divergent "forms" are not considered 

 by ornithologists as entitled to nomenclatural recognition. 

 Some years since a large-sized, large-billed, very red form 

 was described as a subspecies under the name Loxia 

 curvirostra bendirei, based on specimens from eastern 

 Oregon. It was long held in abeyance, however, by the 

 A. 0. U. Committee, and finally rejected on the ground 

 that no definite or distinctive geographic range could be 

 assigned to it. 



This case is cited as an illustration of the wide differ- 

 ences in conditions that obtain in botany and zoology. If 

 the crossbills grew fixed to the soil like plants, and their 

 ecology was equally open to investigation, some cause 

 might be assigned for the development, respectively, of 

 the large-billed and small-billed forms. At present all 

 we know is that the common red crossbill is an exceed- 

 ingly erratic species, nesting apparently with equal fre- 

 quency in mid-winter or in summer, and migrating with 

 extreme irregularity as to season and the regions visited, 

 and characterized by an exceptionally wide range of 

 morphologic variation. The variation in the general size 

 of the individual, and in the size of the bill and in colora- 

 tion may result from different food habits, and the lack 

 of any sharply denned lines of morphologic separation 

 may be due to frequent or habitual interbreeding of the 

 different morphologic strains. The peculiar life habits 



remove it from the field of experimental research, at least 

 for the present. 



Considering utility as the test, the trinomial system 



