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Why are these yellow birds turning red?

by Jocelyn Hudon, Curator, Ornithology

July 16, 2020

Join Dr. Jocelyn Hudon, RAM Curator of Ornithology, as he digs into this strange, colour-shifting phenomenon. Why is it happening, and what could it mean for the future of these birds?


Video transcript:

Several years ago, ornithologists began to notice a fascinating change in the coloration of birds in North America. It was first reported that the tail tips of cedar waxwings – normally yellow – had begun to turn red. Then, additional examples of reddening came to light in other species with yellow feathers, like the White-throated Sparrow, and the Northern Flicker.

Why are these yellow birds turning red?

We were able to trace the color shift to the introduction of an exotic shrub from Japan, whose berries contain an unusual red pigment. The shrub is rare in Japan, but it has become a sprawling, invasive species here in North America. The birds eat the berries from the shrub, and the pigment causes the growing yellow feathers to turn orange or red.

Colors matter to birds, so what does this mean in terms of trying to find a mate? Does this make them more or less attractive? That's something for us to watch and see.