Seed-munching evening grosbeaks now visiting Ohio

A pair of evening grosbeaks - male above, female below/Jim McCormac

Seed-munching evening grosbeaks now visiting Ohio

Columbus Dispatch
December 20, 2020

NATURE
Jim McCormac

On May 23, 1707, Carl Linnaeus was born. The Swedish scientist would revolutionize the naming of organisms with his system of binomial nomenclature. In the Linnaean system, an organism is branded with two names: genus and species. For instance, readers of this column, or at least most of them, are Homo sapiens.

These scientific names are sometimes more descriptive than common names. That’s the case with this column’s subject, Coccothraustes vespertinus. Translated from its Greek and Latin roots, the name means “kernel breaker of the evening”.

The species is far better known as the evening grosbeak. But kernel breaker is apropos, and a glance at an evening grosbeak’s massive bill reveals why. The “evening” descriptor is a bit nonsensical, as the birds are typically most active in the morning.

These robust finches of the north woods are death on seeds, even the hardest of nuts, pits, and stones. Woe to the sunflower seed that crosses a grosbeak’s path.

Even though their sunflower seed bills will skyrocket, most backyard bird feeders would gladly pay the tab to support a flock of ravenous evening grosbeaks. The male is stunning, boldly clad in bright yellow tones and contrasting black tail and wings. The latter are marked with large white patches.

Male grosbeaks’ heads sport conspicuous flared yellow stripes. Their headgear suggests the winged helmet favored by the Olympian God Hermes. Females are much muted in coloration, as is the case with most of our songbirds.

Evening grosbeaks are big news this winter. This species used to stage regular southward incursions into Ohio and points south, but winter invasions have become nearly nonexistent in recent decades.

The evening grosbeak’s stronghold is western Canada and western U.S. mountains. About a century ago, this species began moving eastward and eventually colonized boreal forest regions all the way to the east coast.

This expansion has been tied to increased use of box-elder as an ornamental tree. While grosbeaks do favor the seeds of this scruffy maple for food, I have my doubts that box-elder plantings triggered the large-scale range extension.

Box-elder is a successional species, flourishing in cut-over and disturbed habitats. The Evening grosbeak’s active period of expansion correlates with widespread logging and deforestation of the early 20th century. Great swaths of logged landscapes probably greatly spiked populations of box-elder, as well as other grosbeak-friendly fruit-bearing trees such as hawthorns and plums.

Maturation of forests and other land use changes may no longer favor grosbeaks, and their eastern population has greatly dwindled. Good numbers of evening grosbeaks typically occurred in Ohio in winter about every 2-3 years up until the early 1980’s. After that, they became much scarcer.

Whatever the causes for their decline, a winter invasion of evening grosbeaks is now a monumental event. They quickly recognize feeders as a food source, and many a birder has been delighted to find flocks decimating their seeds this winter.

Thus far this winter, evening grosbeaks have been documented in 59 of our counties. I suspect they’ve been in all 88 counties, and birds might appear anywhere, including your feeders.

Keep an eye out for these large extroverted finches. It might be many years before you get an opportunity to clap eyes on one in the Buckeye State. If you are so fortunate as attract them to your backyard buffet, prepare to increase the birdseed budget.

Naturalist Jim McCormac writes a column for The Dispatch on the first, third and fifth Sundays of the month. He also writes about nature at www.jimmccormac.blogspot.com.