Feathers of the Western Tanager

By eBird Northwest Team May 18, 2018
217 05 Western Tanager 02 (1)

Western Tanager (c) Jim Livaudais 2018

In celebration of the return of North America’s Neotropical migrants, today’s #featherfriday features the male Western Tanager. Many of our most colorful and beloved breeding birds, including warblers, tanagers, orioles, and buntings, actually spend most of their lives outside the United States, wintering in Mexico and Central or South America. The Western Tanager, for example, nests throughout the western US and Canada (breeding farther north than any other tanager), but winters from Mexico to Costa Rica. There, it mingles with flocks of warblers, honeycreepers, and tropical tanagers in habitats ranging from pine-oak woodland to deciduous tropical forest.

This raises the question, much debated among ornithologists, “What is a tanager?” The term has been applied to a large variety of middle-sized, colorful, fruit-eating, forest-dwelling songbirds, which were grouped in the family Thraupidae. A barrage of genetic studies in the past 15 years has shown that many of these birds are not closely related to each other. The North American “tanagers” (all in the genus Piranga) do not in fact belong in the family Thraupidae, but rather in the family Cardinalidae with the cardinals, buntings, and Rose-breasted and Black-headed Grosbeaks. The “true tanagers” in the family Thraupidae are all restricted to the Neotropics. So, the term “tanager” is one of many in ornithology, including “flycatcher,” “warbler,” “grosbeak,” and “sparrow” that are applied to birds that have similar body types and habits, but not a shared evolutionary lineage.

One last feather fact about the Western Tanager: the red in its plumage comes from the rare pigment rhodoxanthin, which must be derived from dietary sources, unlike the carotenoid pigments of Scarlet and Summer Tanagers, which those birds are able to synthesize themselves. This explains why the intensity of color on the head of Western Tanagers is highly variable.

Article by Pepper Trail