Warbling Vireo

Vireo gilvus
STANFORD LOCATIONS:

Uncommon migrant throughout campus. A fairly common breeder in riparian and foothill areas nearby, but not known to breed on campus.
Nest
Location
Nest
Type
Eggs
Mating System
Dev.
Parental Care
Primary &
2ndary Diet
Foraging
Strategy
MF
I: 12 DAYS
ALTRICIAL
SHRUB
 30 feet - 90 feet
(4 feet - 90 feet)
MF
4
(3-5)
MONOG
F: 16 DAYS
MF
BERRIES
HOVER&
GLEAN
BREEDING: Open deciduous and deciduous-coniferous woodland, riparian forest and thickets. ? broods.
DISPLAYS: Female quivers wings, often in response to courtship song of male. Most courtship occurs within 30' of nest. Audubon reported that male struts around female with wings and tall spread.
NEST: Usu high in tree, often lower (<30') in w in tree or shrub; very well made, compact, basketlike deep cup, suspended by rim from prongs of forked twig; of bark strips, leaves, veg fibers, grass.
EGGS: White, spotted with browns, black. 0.8" (19 mm).
DIET: Almost entirely insects, some spiders; few berries.
CONSERVATION: Winters from n w Mexico s to El Salvador. Common cowbird host, does not attempt to destroy their eggs. Has declined in urban areas from pesticide spraying of shade trees.
NOTES: Forages and sings mostly in treetops. Fearless around nest. Both sexes brood.
ESSAYS: Bird Guilds; Brood Parasitism; DDT and Birds; Cowbirds.
REFERENCES: Howes-Jones, 1985.

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Except for Stanford Locations, the material in this species treatment is taken, with permission, from The Birder's Handbook (Paul Ehrlich, David Dobkin, & Darryl Wheye, Simon & Schuster, NY. 1988).