Warbling Vireo, Vireo gilvus

Warbling Vireo, Vireo gilvus victoriae. Photograph taken within a residential community in Alamos, Sonora, November 2019. Photograph and identification courtesy of David F. Smith, Alamos, Sonora.

Warbling Vireo, Vireo gilvus victoriae. Photograph taken within a residential community in Hereford, Arizona, April 2021. Photograph and identification courtesy of Bob Behrstock, Sierra Vista, Arizona (naturewideimages.com).

The Warbling Vireo, Vireo gilvus victoriae, is one of five subspecies of Warbling Vireo, and all five are found in Mexico at various times of the year. They are a member of the Vireonidae Family of Vireos, Shrike-Babblers and Erpornis, which has sixty-three members placed in eight genera, and one of thirty-three global species of the Vireo Genus. They are known in Mexico as vireo gorjeador.

The Warbling Vireo is mid-sized in stature. They are a gray-olive green color with white underparts slightly washed in yellow and undertail coverts. Their face has a moderately distinct white supercilium contrasting indistinctly with a grayish eye line. They lack distinct wing-bars or other contrasting markings or colors. The males and females are similar in plumage. Their bill is black, brownish black or dark grayish brown and the lower mandible has a pale base; their iris is dark brown, and their legs are blue gray.

In Mexico the Warbling Vireo is considered to be a medium to long distance, partial migrant and they are found in mature mixed deciduous forests, especially along streams, ponds, marshes and lakes in riparian areas at elevations up to 3,000 m (9,840 feet). They are seldom encountered as individuals and normally found within a mixed species feeding flock. Their diets primarily consist of insects supplemented with seasonal fruits. Their life spans have not been determined. The Warbling Vireo is known for its persistent singing and normally heard before they are seen.

The majority of the Warbling Vireo’s found in Mexico are winter visitors and found throughout the country with the exception that they are absent from the Yucatán Peninsula. They are year-round residents in the states of Jalisco, Michoacán and Guerrero. The victoriae subspecies is found in the Cape Region of Baja California Sur and southern Sonora.

From a conservation perspective the Warbling Vireo is currently considered to be of Least Concern, with stable, widely-distributed populations. Their populations vary, increasing in some regions and decreasing in others. Human development has helped the expansion of their range in some areas.