The Colour-Producing Structure in the ‘Dominant Grey’ Budgerigar

Abstract

THERE are some distinct structural differences between the feathers of the ‘Dominant Grey’ budgerigar and those of other races. In the wild coloured form the feathers of the lower abdominal region show in transverse section a somewhat triangular outline, and the vacuoles are arranged along the median axis of the section (see Fig. la). In the grey bird, the outline appears rounder, and the medulla of the barb is composed of a larger number of relatively small cells, the vacuoles occupying more or less the central parts of the cells and appearing therefore more equally distributed (see Fig. 1b).