Question

What is the molting strategy of Indigo Buntings and what do they look like during each stage of molt?

Answer 1

Many birds replace their feathers with a fresh coat once in a year atleast through the process of molting. The adult male indigo buntings change their colour completely during a molt.

These birds in breeding plumage actually have black feathers, but due to the diffraction of light by the structure of the feather, they appear as blue. The colour changes from black to blue to turquoise as the angle of reflected light changes.

Their appearance during each stage of molt is explained as follows-:

a) Natal down- After hatching, the chick is sparingly covered with long downy filaments.

b) Juvenal plumage- Brown is the prevailing colour of this stage, paler below with streaks on the breast. Females appear wholly brown, but males have a greenish blue tint mostly marked in the tail.

c) First winter plumage- This is the third stage of plumage. In males, the feathers of the throat become tinged with pale blue. The females remain dull brown and gray.

d) First nuptial plumage- This is the fourth stage of plumage. The breeding males become completely bright blue or with the scattering of bright blue feathers which are mixed with the brown, gray or pale blue worn out feathers. The females undergo very little or no molting in this stage.

e) Adult winter plumage- In this fifth stage, all the feathers are renewed in both males and females. These birds now acquire blue-edged primary coverts.The bright blue feathers have different structures in young and old birds.

f) Adult nuptial plumage- In this stage, the birds start appearing more brighter than they do in the fall.