USFWS Migratory Birds - While the color of many birds' feathers is from natural pigment, the blue in a blue jay's feathers comes from the way the light reflects off the feathers.

A trick of nature: Blue jays aren't really blue

World's oldest blue bird found via fossil feathers

Feather Friday

Plumages, Molts, and Structure - Blue Jay - Cyanocitta cristata - Birds of the World

Why Are Some Feathers Blue?, Science

Feather Friday

A trick of nature: Blue jays aren't really blue

The pigment in Blue Jay feathers is melanin, which is brown. The blue color is caused by scattering light through modified cells on the surface of the feather barbs. : r/Awwducational

Spatially modulated structural colour in bird feathers

Bird Feathers Produce Color Through Structure Similar to Beer Foam

There is No Such Thing as a Blue Bird – National Geographic Education Blog