It is an unforgettable sight to see a flock of sunset-hued Western Tanagers move through the trees in our parks and gardens. Western Tanagers spend most of their time in the tree canopy, occasionally coming down to eye-level looking for food and water. Good numbers will be moving through over the next few weeks of May. Western Tanagers arrive from wintering grounds in the mountains of Mexico and south to Costa Rica. There is a record of a Western Tanager banded in Bend, Oregon on May 25, 1978 and recovered in the western mountains of Guatemala on November 11, 1978. They eat a variety of insects in spring and summer, including bees and wasps as well as fruits and berries as they ripen through the summer.
The Black-headed Grosbeak is one of our prominent spring migrants and a frequent visitor at bird feeders. They announce their presence with an exuberant, robin-like song. Black-headed Grosbeaks arrive during the last week of April and the beginning of May, from Western and South-central Mexico. After breeding, they migrate south to Arizona and northwest Mexico (Sonora and Sinaloa) to undergo a complete molt during the “second spring” monsoon. These June-August monsoon rains bring an abundance of food which supports the birds during their energy-consuming molt. They then migrate further south, usually by October. Black-headed Grosbeaks belong to the Cardinalidae family (which includes the Western Tanager and the Lazuli Bunting). They are not related to the Evening Grosbeak, which is a type of finch in the family Fringillidae.
The colorful Bullock’s Oriole starts arriving in Western Oregon’s deciduous forests from late April and early May. They most often breed in oak woodlands or riparian areas along rivers and streams, and are sometimes found in orchards and homesteads with large deciduous trees. Look for their hanging, purse-like nests as the season progresses. Bullock’s Orioles eat a variety of insects, especially moth larva such as tent and leaf-rollers caterpillars, and some summer fruits. As with a few other migratory passerines in the West, the Bullock’s Oriole carries out a molt migration. By mid-August they our leaving our area, heading to Northwest Mexico, where they stage for about 7 weeks to molt. Then they continue to wintering grounds in Mexico and Central America.
The Warbling Vireo is a widespread breeder in riparian corridors and deciduous forests throughout Oregon. Watch for these unassuming, pale gray birds with a faint mask, as good numbers move through our area singing their short, scratchy and cheerful song. Peak numbers arrive in early May from wintering grounds that stretch from west Mexico to Nicaragua. The western population of Warbling Vireos migrates south to the foothills of Northwest Mexico (Sonora and Chihuahua), where they stage for 6-8 weeks in August and September to molt, then continue to wintering grounds.
The Lazuli Bunting is a stunning spring delight. The male sports brilliant, turquoise head feathers, and sings a sweet, warbled song from his breeding habitat in open woodlands, shrubby patches and thickets on the edge of fields and meadows. Buntings begin arriving in the Portland area from western Mexico and Baja during the last week of April, and numbers build through mid-May. The Lazuli Bunting begins to molt in late summer on its breeding grounds, but then stops partway through the process and migrates to Sonora, Arizona and New Mexico to finish the molt. Then in November, they fly south to their wintering grounds. Historically, the Lazuli Bunting was a much more common breeding bird in the Northern Willamette Valley.