Black-headed Grosbeaks among our summer visitors

Many Boundary County residents have been seeing black-headed Grosbeaks (Pheucticus melanocephalus) during this summer. Perhaps not as numerous or quite as spectacular as Western Tanagers, these are nevertheless very attractive members of the finch family. They winter in Mexico, and spend their summers in the western half of the United States.

Like most finches, they are seed-eaters, and have been seen at the seed feeders. They will also eat fruit and insects, and interestingly they are one of the few birds that can eat the normally poisonous monarch butterfly. The females are less showy than their male counterparts.

Black-headed Grosbeaks’ massive bills make them well equipped for cracking seeds, but those beaks are just as useful for snatching and crushing hard-bodied insects or snails. Black-headed Grosbeaks eat mostly insects, seeds and berries. In summer they feed on many insects, including beetles, caterpillars, wasps, bees, flies, and many others, also spiders and snails. They feed on seeds of various weeds, and eat berries of many plants as well as some cultivated fruit. Young are fed mostly insects at first.

Black-headed Grosbeaks glean most of their food in the treetops and understory, less frequently lunging at prey, and occasionally snatching flying insects from the air. They hop on branches or at feeders, cracking seeds and hard-bodied insects with their heavy bills.

After spring migration, tight-knit pairs form quickly. Males court females with vigorous singing and striking displays called “nuptial flights” lasting 8-10 seconds: the male flutters up from a perch, singing and spreading his wings and tail to reveal the bold white-on-black patterns, rising several feet before settling back on the same perch.

Singing helps with territorial defense, although both males and females will attack other grosbeaks that intrude. Aerial grappling of the grosbeaks can be ferocious. They tend to tolerate species such as warblers that come near the nest, but they attack predators including Steller’s Jays. Both males and females sing on the nest, and they share the chick-rearing duties of sitting on the eggs and feeding the young about equally.

The nest is placed in a tree or large shrub (usually deciduous), 3 to 25 feet above the ground, usually about 10 to 12 feet up. The nest is built mostly or entirely by the females and is an open cup, loosely constructed and bulky, made of twigs, weeds, rootlets, pine needles, lined with fine plant fibers, rootlets, and pine needles, lined with fine plant fibers, rootlets, and animal hair.

I found out that Black-headed Grosbeaks are attracted to sunflower seed feeders. They will even nest in backyards and gardens where enough cover is available and water is nearby.

Enjoy Boundary County and all its beauty!