By Jim Gain
Learn 100 Common Valley Birds is a photo blog series highlighting the 100 most common Valley bird species.
Post #20 in the Learn 100 Common Valley Birds series. (Species 30, 31 & 32/100)
Wilson’s Warbler – Species #30
The Wilson’s Warbler (Cardellina pusilla) is a small, brightly colored songbird that can be found in the Central Valley of California during its migration season. These birds are about 4.5 inches long and have a wingspan of approximately 6 inches. They are bright yellow in color with a black cap on their head.
Wilson’s Warblers are insectivores and are often found flitting through vegetation in search of insects. They are known for their distinctive song, which is a series of high-pitched notes that sound like “tee-tee-tee-tee-tee.”
Despite their small size, Wilson’s Warblers play an important role in the Central Valley’s ecosystem by helping to control insect populations. However, like many bird species, they face threats from habitat loss and climate change, making conservation efforts crucial for their continued survival. Protecting the habitats that these birds rely on, such as riparian areas and wetlands, is essential to ensuring that they can continue to migrate through the Central Valley and beyond.
Yellow Warbler – Species #31
The Yellow Warbler (Setophaga petechia) is a small, brightly colored songbird that inhabits the Central Valley of California during the breeding season. These birds are easily recognized by their bright yellow plumage, which is accented by rusty red streaks on the breast and flanks.
Yellow Warblers are typically found in riparian habitats such as streamside woodlands, hedgerows, and willow thickets. During the breeding season, they construct cup-shaped nests made of grasses and other plant materials, which are often lined with spider webs and feathers. Females typically lay 3-5 eggs, which hatch after a 10-12 day incubation period.
Yellow Warblers are insectivorous and feed primarily on small insects such as caterpillars, beetles, and spiders. They are also known to occasionally feed on fruit and nectar. These birds migrate south to Mexico, Central America, and the Caribbean during the winter months. The conservation status of Yellow Warblers is currently listed as Least Concern by the International Union for Conservation of Nature (IUCN), but habitat loss and degradation are potential threats to their populations.
Warbling Vireo – Species #32
The Warbling Vireo (Vireo gilvus) is a small, olive-gray bird with a white underbelly and supercilium (eyeline). It measures about 4.75 inches in length and has a wingspan of approximately 8 inches. The species is known for its distinct, high-pitched warbling song, which it uses to communicate with its mate and establish its territory.
In the Central Valley of California, the Warbling Vireo is a fairly-common neotropical migrant, passing through in late April or early May and making its return trip back south in August or September. The bird breeds in higher elevation riparian habitats, including streams, rivers, and creeks, where it builds a cup-shaped nest in the fork of a tree or shrub.
Warbling Vireos are known for their distinctive, warbling song, which is often described as sounding like “three eight, three eight, three eight.” They are a migratory species and spend the winter in Mexico, Central America, and South America before returning to their breeding grounds in the spring. Overall, Warbling Vireos are an important and fascinating part of the avian community in this region, and their presence is a sign of a healthy and diverse ecosystem.
Previous posts from the Learn 100 Common Valley Birds series:
Reflections of the Natural World 
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