Blue Grosbeak, Passerina caerulea

Blue Grosbeak, Passerina caerulea caerulea, Male. Photographs taken at a backyard bird feeder within a residential community in Fort Lauderdale, Florida, October 2022. Photograph and identification courtesy of Faith Hubsch, Fort Lauderdale, Florida.

Blue Grosbeak, Passerina caerulea interfusa, Female. Photograph taken within a residential community in Hereford, Arizona, May 2021. Photograph and identification courtesy of Bob Behrstock, Sierra Vista, Arizona (naturewideimages.com).

Blue Grosbeak, Passerina caerulea interfusa, Female. Photograph taken within Xochicalco, Morelos, March 2018. Photograph and identification courtesy of David F Smith, Alamos, Sonora.

Blue Grosbeak, Passerina caerulea interfusa, Male. Photograph taken within a residential community in Hereford, Arizona, May 2011. Photograph and identification courtesy of Bob Behrstock, Sierra Vista, Arizona (naturewideimages.com).

Blue Grosbeak, Passerina caerulea interfusa, Male. Photograph taken within a residential community, Alamos, Sonora, February 2019. Photograph and identification courtesy of David F Smith, Alamos, Sonora.

Background and Identification

The Blue Grosbeak, Passerina caerulea interfusa, is one of six subspecies of Blue Grosbeak, five of which are found in Mexico. They are a member of the Cardinalidae Family of Cardinals and Allies, which has forty-nine members in fourteen genera and is one of seven global species of the Passerina Genus. This species is known for its vibrant blue plumage and larger-than-average, robust build compared to other grosbeaks. Blue Grosbeaks feed on wild and cultivated grain seeds but are rarely spotted on farms and other suburban areas. The Blue Grosbeak has been poorly studied and limited information about their behavioral patterns and biology has been documented. They are known in Mexico as Azulillo Grande.

The Blue Grosbeak is large in stature for a songbird, that are 15 cm (5.9 inches) to 18 cm (7.1 inches) in length. They are a sexually dimorphic species, males are purplish-blue with two brown wing bars, and a two-toned beak that is black (upper) and silver (lower). They have black lores that extend down to the lower mandible and chin, dark blue patches of purplish-blue feathers edged in black or brown, and shiny black flight feathers. Females are brown with few blue feathers on the upper parts and have two brown wing bars.

Habitat and Geographical Range

Blue Grosbeaks inhabit abandoned fields, forest edges, hedgerows, stream edges, deserts, mesquite savanna, and southern pines. They are frequently found near water sources such as rivers, streams, and wetlands, but are seldom seen in suburban habitats. Habitats with dense vegetation for nesting and foraging are preferred.

The Blue Grosbeak is a migratory bird found throughout the southern United States and Mexico. Both subspecies winter in Mexico and Central America and breed in the United States during the summer months. The caerulea subspecies winters in southeastern Mexico, mostly on the Yucatan Peninsula. The interfusa subspecies is found year-round in Chihuahua and Sonora and populations from the United States winter in western Mexico from southern Sonora, south to Jalisco, and west to Mexico City with a few individuals being found in Baja California Sur.

Common Misidentifications

The Blue Grosbeak can be confused with other blue-colored birds, particularly the Indigo Bunting, Passerina cyanea, and the Lazuli Bunting, Passerina amoena. The Indigo Bunting is smaller, lacks the chestnut wing bars, and has a more uniform blue coloration. The Lazuli Bunting, found in the western United States, has a blue head and back but features a white belly and orange breast, which differentiates this species from the entirely blue body of the male Blue Grosbeak. Additionally, the Blue Bunting, Cyanocompsa parellina, found in parts of Central America, is similar but generally smaller and lacks the chestnut wing bars.

Conservation Status

From a conservation perspective the Blue Grosbeak is currently considered to be of Least Concern. Their population is considered stable, and they are relatively common within their range. However, habitat loss and degradation due to agriculture, urban development, and changes in land use can pose threats to their populations. Pesticide use in agricultural areas can also impact their food supply.