A feature which is also of some use in distinguishing geographical races is the colour of the bases of the feathers. In southern birds these are nearly always very dark, in Central Indian birds they vary a great deal from pale dirty white to dark, whilst in the northern mountain birds when fully adult they are generally pale and often pure white. Andaman birds seem invariably to have the bases to their feathers a very pure white, and differ in this respect from, their nearest allies in Assam and
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Fig. 4. — Head of C. coronoides.
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Fig. 5. — Foot of C. coronoides.
Burma, from which it may be found necessary to separate them; they agree with these, however, in their very heavy bills.
As so much of the material for examination in museums is unsexed, it has been very difficult to draw conclusions from measurements. It must be remembered, however, that females on the whole run smaller than males and certainly have smaller, slighter bills. Although non-migratory birds and in their wilder
