The Black-headed Grosbeak is a fairly common migrant that spends the summer in Washington’s low-elevation forests and riparian corridors. It arrives in May and leaves by September. It prefers deciduous vegetation so public locations where it can be found in Edmonds include the Willow Creek Hatchery and Yost Park. If you offer larger sunflower seed feeders at which this species can perch, you can sometimes see it in your yard. You can often hear its sweet song in spring, caroling down from tree tops.
The male Black-headed Grosbeak does not molt into adult plumage until two years of age. Younger males often look similar to adult females. That is why we are not sure whether the bird in Blair’s second photo is an adult female or a subadult male.
Diet is made up mostly of insects, seeds, and berries. In summer the Black-headed Grosbeak eats many insects such as flies, bees, wasps, beetles, and caterpillars. It also eats a variety of weed seeds and berries. This grosbeak forages mostly in shrubs and trees
The Black-headed Grosbeak population winters in central Mexico. This is also where most monarch butterflies spend the winter. Although toxins in monarchs make them poisonous to most birds, a few species, including the Black-headed Grosbeak, can eat them. An eight-day cycle of feeding apparently allows time for this grosbeak to eliminate the monarch’s toxins before feasting on more butterflies.
As do many birds, the male Black-headed Grosbeak sings to defend his nesting territory. Courtship displays include performing song-flights above the female, and flying with his wings and tail fully spread while singing continuously. The female builds the nest in a tree or large shrub, usually about 10-12 feet above ground, although it can be higher or lower. The nest is a loosely constructed open cup of twigs, rootlets, weeds and pine needles, lined with animal hair and fine plant fibers. Both sexes incubate the three to four eggs for a period of about two weeks. The young climb out of the nest after 11-12 days. They remain in nearby trees to be fed by their parents for another two weeks, until they are able to fly.
The oldest known Black-headed Grosbeak, a male, was 11 years and 11 months of age when it was recaptured and re-released during a Montana banding operation.
The conservation status of the Black-headed Grosbeak is that of least concern because the population, estimated at 14 million, is stable or increasing. Although urbanization has destroyed some of its prime habitats, it is an adaptable species.
The song of the Black-headed Grosbeak can be heard here: http://www.xeno-canto.org/324996. Both the male and female sing. The female sings a simplified version of the male’s song.
— By Carol Riddell
Carol Riddell manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.