If you have ever taken a close look at a cedar waxwing, you probably noticed that some of the feathers on its wings seem to be tipped in red wax.  In truth, it is not wax at all.

The red that we see is located in the flattened tips of the main shafts (rachis) of the bird’s secondary wing feathers.  The material that produces the brilliant red color is a carotenoid pigment.  For the first few years of a cedar waxing’s life, the number and size of these droplets increases each time these feathers are molted.  Consequently, the wings of young cedar waxwings display few, if any, red tips.

The function of this plastic-like substance remains a mystery.