Habitat
Plumbeous Vireos breed mostly in dry montane coniferous and mixed coniferous-deciduous forests of western North America, from about 3,000 to 8,200 feet elevation (up to 10,000 feet in Mexico). In the Great Basin, they also nest in deciduous woodlands along rivers. In these breeding areas, typical tree species include ponderosa pine, pinyon pine, Douglas-fir, quaking aspen, Gambel oak, silverleaf oak, narrowleaf cottonwood, black cottonwood, water birch, box elder, chokecherry, mountain mahogany, juniper, ash, willow, maple, and sycamore. Plumbeous Vireos are often found along the sides and bottoms of canyons. Migrants use mountain habitats but also travel along stream drainages or desert washes with cottonwoods, willows, mesquite, or acacia. In Mexico, Plumbeous Vireos use sea-level mangrove forests, lowland rainforest, and thorn forest up through virtually all vegetated habitats to pine-oak forests near 10,000 feet (but apparently not in fir forests of higher elevations). In some parts of Mexico, wintering Plumbeous Vireos frequent the same habitats as resident subspecies.
Back to topFood
Plumbeous Vireos eat mostly insects and fruit, which they take by gleaning and plucking from vegetation. Like other vireos, Plumbeous forage rather slowly, moving by hops and short flights through trees and large shrubs and inspecting the surfaces of leaves and small branches and twigs for insects, which they usually seize in the bill or pounce on after a hop or flight. They sometimes peer into or probe clusters of needles or bark crevices for prey. On occasion, they hover-glean or flycatch but rarely suspend themselves upside-down like smaller songbirds in this habitat. In most habitats, they forage in conifers (pines, junipers) rather than deciduous trees, with the exception of oaks, which often harbor abundant caterpillars and other prey. They swallow small prey items whole but may beat larger prey against branches before eating, sometimes dismembering them with the bill while holding them with a foot against a branch. Prey items include adult and larvae of moths, butterflies, bugs (especially stinkbugs), bees, wasps, beetles, flies, treehoppers, leafhoppers, scale insects, and cicadas. They also eat spiders and small fruits.
Back to topNesting
Nest Placement
The male selects the nest site, typically in a forked tree branch, which he shows to the female with elaborate gestures and singing, sometimes attaching nesting materials to the site.
Nest Description
The female does most of the nest construction, suspending an open cup from a forked tree branch, and using grasses, rootlets, bark strips, and hair. She lines the nest with grasses and rootlets, and decorates it with cocoons, lichens, moss, and catkins. Nests measure on average about 3.3 inches across and 2.4 inches tall, with interior cup 2.2 inches across and 1.7 inches deep.
Nesting Facts
Clutch Size: | 3-5 eggs |
Egg Description: | Creamy white with sparse dark spots around larger end. |
Condition at Hatching: | Naked and pink, with eyes closed. |
Behavior
Male Plumbeous Vireos arrive on breeding grounds earlier than females and begin to establish territories by singing from prominent perches in trees around the territory. Males sometimes reuse their territory from the previous nesting season. Territories range from about 1.5 to 5 acres. As females arrive, males display to them much in the same manner as the closely related Blue-headed and Cassin’s Vireos, by calling softly as they sway side to side, fluffing out the body feathers, fanning the tail, and opening the wings slightly. Male Plumbeous, however, do not chase females in flight as other vireos do. Pairs may begin nest building within a day of pair formation. Plumbeous Vireos appear to be monogamous in their mating system. Males drive rival males away from nests and out of the territory by threat displays (similar to courtship posture), chattering calls, and aerial chases. Males sometimes feed incubating females, and both sexes share incubation and chick-rearing duties. Males perform most defense of the nest and young. Once the young have fledged, family groups forage together for a time, often joining mixed-species flocks of foraging songbirds. Family groups disband prior to migration. Wintering birds may forage in mixed-species flocks.
Back to topConservation
According to the North American Breeding Bird Survey, Plumbeous Vireo populations declined by an estimated 2.4% per year between 1968 and 2015, suggesting a cumulative decline of 70% during that time. Partners in Flight estimates a global breeding population of 3.5 million birds and rates the species a 13 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. The greatest conservation threat to this species probably involves habitat loss and degradation, the result of clearcutting and development for housing, agriculture, and livestock operations. Habitat disturbance also increases opportunities for nest parasitism by Brown-headed Cowbirds.
Back to topCredits
Goguen, Christopher B. and David R. Curson. (2012). Plumbeous Vireo (Vireo plumbeus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.
Partners in Flight (2017). Avian Conservation Assessment Database. 2017.
Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.