This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the plumbeous vireo.
A seasonal inhabitant of our local ponderosa pine, Gambel oak and juniper forests, the plumbeous vireo is perhaps most detectable by sound when they arrive in the spring. Males typically arrive on breeding grounds here first, and seek to establish territories, singing their textured (often described as “burry”) song of ascending and descending notes. At it’s simplest, “Cheechurri?, Cheechuroo.” It can almost come across as a very melodic question and answer series. As the breeding season wanes, both sexes issue their harsher and more regular che-cheche calls, locating and scolding as they move through the forest.
In Latin, the word plumbum, and resulting chemical symbol Pb, refer to lead; thus, the name. Adult males and females both have a leaden gray upper portion (head/shoulders/rump) with white undersides and flanks that oftentimes have a light yellow or green wash. Their wings have two distinct white wing bars and most recognizable is a pair of white spectacles that wrap 3/4 around their eyes, bridging over their thick bills.
These birds will often move quite fastidiously through the tree canopy (difficult to locate for the photographer), efficiently gleaning insects, and occasionally stopping and tipping their heads curiously to locate prey. They seek out caterpillars, beetles, wasps, bees, spiders and occasionally fruit when available.
In addition to the slightly drabber warbling vireo, the plumbeous have a regional cousin known as the Cassin’s vireo. This species looks very similar, donning the same white spectacles, but have a greener back and a decidedly more olive casting on their breasts and flanks.
These small insectivores breed as far north as southeastern Montana and fly south to winter in Mexico, often in mixed flocks. As with other long-distance migrants, these birds navigate a landscape that has seen habitat fragmentation, degradation and loss, so the more that we can provide native forage and shelter for them in our backyards, the better they stand to fare in future years.
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