No strangers to the Big Bend area, tanagers are some of the most colorful birds in the spring and into late summer here. And one of the favorites for both color and song is the Western Tanager.
The breeding range of these birds extends from southeastern Alaska to south through the western states and West Texas. Most Western Tanagers arrive in the Trans-Pecos and High Plains regions during spring from early April to late May. They usually breed in Texas from late April to mid-August. In the fall, they migrate south to central Mexico for the winter.
Big Bend National Park is on the migratory flyway of several tanagers as they migrate north and south. Thus, several species of tanagers can be found, especially in the Chisos Mtns., but also in the neighboring area. I enjoyed watching and listening to these colorful birds last May around Cedar Springs area on Terlingua Ranch. A local resident recently photographed a Western Tanager hunting for insects in a clutch of creosote.
Most red birds owe their colors of red, yellow and green to a variety of plant pigments known as carotenoids, which are deposited in their feathers. The Western Tanager gets its scarlet head feathers from a rare pigment called rhodoxanthin. Unable to make this substance in their own bodies, Western Tanagers probably obtain it from their diet of insects that feed on conifer (pine, fir, yew, and cedar) needles, and small fruit (especially of the honeysuckle) which contain the pigment. These pigments are stored specifically in their crown feathers to give them their red appearance.
Another related species of interest is the Flame-colored Tanager. Historically common only to central Mexico, their range has increased north over the last decade. They have become more common in the Sky Islands of Arizona with a few documented sightings in the Chisos Mtns. of BBNP. Interestingly, because their DNA are closely matched, more than of other tanagers, the Western and Flame-colored Tanagers are quick to mate and hybridize. Increasing documented sightings of hybrid birds are reported in Arizona the last several years. It is not unusual for closely related species to hybridize when their border habitats overlap.