Black-headed Grosbeak

The Black-headed Grosbeak is a robust, large-billed songbird that fills the western ecological role of the closely related Rose-breasted Grosbeak, with the two species hybridizing in a narrow overlap zone on the Great Plains. Adult males have a black head, black-and-white patterned wings and back, and warm cinnamon-orange underparts and nape, while females are streaky brown above with buffy-orange underparts, a bold white eyebrow stripe, and a much smaller, less contrasting bill pattern than the male.

One of the few North American birds able to safely eat toxic monarch butterflies, Black-headed Grosbeaks play a notable ecological role at monarch overwintering sites in Mexico, where they can consume large numbers of the cardenolide-laden insects that are poisonous to most other predators.

Key Field Marks

• Massive, thick, pale conical bill
• Adult male: black head, black-and-white patterned back and wings, cinnamon-orange underparts and collar
• Female/immature: streaky brown above, buffy-orange below, bold white eyebrow stripe, streaked flanks
• Yellow wing linings visible in flight (both sexes)

Similar Species

• Rose-breasted Grosbeak males have white (not cinnamon-orange) underparts with a rose-red breast patch; the species hybridize where ranges meet on the Great Plains.
• Female Black-headed Grosbeaks can resemble large sparrows or female orioles but have a much heavier bill and yellow wing linings.

Habitat

Breeds in deciduous and mixed woodlands, riparian corridors, oak woodlands, and forest edges throughout the western United States.

Range

Breeds from British Columbia south through the western United States into Mexico. Winters primarily in Mexico, including at high-elevation fir forests that host overwintering monarch butterflies.

Migration

A medium- to long-distance migrant traveling between western breeding grounds and Mexican wintering areas each year.

Behavior

Black-headed Grosbeaks forage actively in the canopy and understory, and, notably, some individuals feed on toxic monarch butterflies at Mexican overwintering colonies, tolerating the cardenolide toxins that deter most other predators.

Voice

The song is a rich, rolling warble similar to an American Robin's but more fluid and continuous; the call is a sharp, distinctive "eek" similar to the Rose-breasted Grosbeak's.

Feeding

Feeds on insects, seeds, berries, and fruit; readily visits sunflower feeders and is one of the few birds able to eat monarch butterflies without harm.

Nesting & Breeding

Builds a loose cup nest of twigs and plant material in a shrub or tree. Both parents share incubation of 2-5 eggs and feeding duties, and males, like Rose-breasted Grosbeaks, occasionally sing from the nest.