Iridescence, however, occurs when an object's physical structure causes light waves to combine with one another, a phenomenon known as interference. In constructive interference, light waves combine so that the crests and troughs line up to reinforce each other, increasing the vibrancy of the reflected color.

How does iridescence work in feathers?

Iridescent Feathers

The iridescent colors of the gorget are the result of the refraction of incident light caused by the microscopic structure of the feather barbules. ... As the viewing angle changes, the refracted light becomes visible in a glowing, shimmering iridescent display.

How do you explain iridescence?

Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfly wings and seashell nacre, as well as certain minerals.