On Display—The Western Tanager, by Tina Mitchell

An amazing variety of birds in the western hemisphere are called “tanagers”—estimates range from 300 to 400 species in all.  During breeding season, the U.S. routinely hosts only four tanager species, all closely related congenerics:  Western, Summer, Hepatic, and Scarlet. Westerns are by far the most common in this county; the San Diego County Birding Atlas shows only a handful of confirmed breeding pairs of Summer Tanagers while Hepatics and Scarlets occur only as unusual vagrants. Almost as widespread throughout the western U.S. as they are colorful, Western Tanagers occupy a variety of habitats from foothills to subalpine regions. They range farther north than any other tanager species, breeding in northwestern Canada and southern Alaska. In San Diego County, Westerns nest in the pine–oak forests of mountains, although they are generally not common there. However, they move widely through the county during migration.

Western Tanagers don’t stay long here.  For just a few months each year, they grace us with their stunning presence.  Although arguably among the most dazzling of San Diego County’s Neotropical migrants, they frequently escape the notice of those who do not recognize the male’s quiet two-syllable “pit-ick” call or his easy-to-miss American-Robin-esque-but-much-simpler song. Westerns begin to arrive on their breeding grounds in late April and most typically head back to their wintering grounds in Mexico and Central/South America beginning in late August and September.  In winter the species is rare but a regular in the county, occurring almost exclusively in urban parks.

One of my favorite nature writers, Pete Dunne, described the Western Tanager as “a bird so garishly colorful that it seems painted by a child.”  Well, one person’s garish is another person’s stunning, in my opinion.  A bit smaller than a European Starling, the adult male in breeding plumage is truly a visual knockout, with black wings and back, splashes of white and yellow on the wings, yellow underparts and uppertail coverts, and a spectacular red face and head.  Females and immatures flash much less “bling,” with yellowish heads and underparts, olive wings and tails, two subdued wing bars, and gray backs.

The Western Tanager feeds predominantly on insects during the breeding season, but it also incorporates fruits and berries into its diet whenever it can. At other times of the year, fruits and berries constitute a major portion of the diet. (On cold spring days when we lived in Colorado, I have even seen them eating suet at our bird feeders.)  Many birds with red feathers—including the Western’s congeners, the lovely Scarlet and Summer Tanagers—create those striking pigments by directly converting carotenoid pigments in the food they eat into the red coloring in their feathers.  However, in order to produce their stunning red heads, Western Tanagers actually may need to eat insects that have ingested a rarer pigment (rhodoxanthin) found in conifer buds. Not surprisingly then, the Western Tanager’s breed­ing distribution in San Diego County corresponds to the higher mountains supporting larger stands of conifers.

The Western Tanager’s scientific name—Piranga ludoviciana—directly reflects the vast tanager family’s historical roots in South America.  The genus name, Piranga, derives from the word used by the Tupi tribe of the upper Amazon Basin for any small bird.  The species name, ludoviciana, honors Louis XIV of France, arising from the fact that the Western Tanager was first found in the area of the Louisiana Purchase.  Even the common name harkens back to the Tupi language, since “tanager” is their name for this particular family of birds.  Finally, “western” simply refers to this species’ range in the U.S., breeding exclusively west of the 100^th meridian.

However, despite all of the Pirangas’strong similarities to the structure and ecology of other species in the tanager family (Thraupidae), genetic evidence currently suggests that North America’s species in the Piranga genus actually are more closely related to the Cardinalidae family, which includes cardinals and grosbeaks.  Lots of mysteries still remain in establishing the taxonomy of the tanagers, so stay tuned for more possible switches.

Regardless of their family, male tanagers of all species feature eye-popping color combinations, reaching their greatest diversity in Central and South America.  Here’s a hint that might come in handy if you’re ever birding in, say, Ecuador, where tanager species number near a hundred.  If you spot a medium-sized bird you can’t identify, just nod knowingly and guess “tanager.”  Given the base rate of tanager species living there, you have a darn good chance of being right—and amazing your travel companions.