If you hear an especially rich, sweet warble coming from the trees next spring, take a closer look. You may be hearing one of our colorful seasonal visitors: the Black-headed Grosbeak (Pheucticus melanocephalus).
Black-headed Grosbeaks are substantial songbirds, with chunky bodies, relatively short tails, and enormous triangular bills built for cracking seeds and nuts. Breeding males are particularly striking, with burnt-orange bodies, black heads, wings and tails, and bold flashes of white on their wings. Females and immature males are more subtly colored, with boldly striped heads, streaked brown backs, and warm tawny breasts.
A Springtime Return
Black-headed Grosbeaks spend the winter in Mexico and return north in spring to breed throughout much of the western United States, including coastal California. They build relatively flat, woven nests tucked into dense, leafy vegetation, and both males and females sing.
Their song can sound a little like an American Robin that has taken singing lessons: a rich, musical warble with rapidly rising and falling passages, but generally more fluid, mellow and sweet.
An Iron Stomach
Here’s where the Black-headed Grosbeak gets really interesting.
They are among the few birds capable of eating monarch butterflies, whose bodies contain toxic compounds acquired from the milkweed plants they ate as caterpillars. Black-headed Grosbeaks can tolerate those toxins and have been observed feeding on overwintering monarchs in Mexico. Their digestive abilities also allow them to consume foods that contain compounds many other animals avoid, including mistletoe and poison oak.
And don’t let that enormous seed-cracking bill fool you. More than half of their diet can consist of large, hard-shelled insects. They also have a sweet tooth and may visit backyard jelly and nectar feeders intended for orioles.
Look—and Listen—for Grosbeaks
When Black-headed Grosbeaks return in spring, your ears may find them before your eyes do. Listen for that flowing, robin-like song coming from leafy trees, and then look for a chunky bird with a very impressive bill.
If you’re lucky enough to spot a breeding male, the combination of brilliant orange, black and white is hard to mistake. But keep an eye out for the more subtly patterned females and immature birds, too.
The next time you’re exploring the ENC—or simply listening to the birds in your own neighborhood—watch and listen for this striking spring visitor.
Photos by James Kendall. Text adapted from information compiled by Betty Kanne for ENC’s Bird of the Month.