Proc. IV. Int. Orn. Coxcr. Pl. III. 



METHOD OF ILLUSTRATING CLIMATIC OR GEOGRAPHIC VARIATION 



IN BIRDS. 



The leading types of the twenty odd races 01 Song- Sparrow ( Melos biza cinerea 

 cinerea) are placed on the chart near the centre of their respective breeding ranges. 

 The ranges are coloured to correspond with the prevailing tone of the plumage of the 

 birds inhabiting them. A descriptive label explains the significance of this striking 

 variation in colour and in size. 



