Photo courtesy Charles Martinez
This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the evening grosbeak.
A misconception about this bird’s behavior, by early explorers who believed it sang only at dusk, put the “evening” in its name. Anyone familiar with these birds at feeders knows that they are noisy all day long. They don’t really sing, but their calls are distinctive.
Grosbeak is derived from French words meaning thick beak. Evening grosbeaks share this trait with grosbeaks in the cardinal family, but they are more closely related to birds in the finch family.
The colorful male is a golden color with a large white patch on his black wings. A bright yellow eyebrow accentuates his dark head and at this time of year his bill is greenish. Females are more gray brown with greenish tones and white-tipped tails.
In summer, they eat insects including spruce budworm, caterpillars and aphids, but their strong beaks allow them to specialize on large seeds. They can exert enough pressure to crack a seed as tough as a cherry or olive pit, and pine seeds are a staple in their diet.
Traveling in flocks, they will wipe out sunflower feeders. Observations have determined that one bird is capable of cracking more than 90 sunflower seeds per minute.
Evening grosbeaks are permanent residents of southern Canada and the western mountains. They wander widely in search of food, with numbers rising and falling in relation to availability of pine seeds on their breeding grounds. In the last 20 years, reports from Project Feederwatch, ebird.org and Christmas Bird Counts have shown alarming population declines throughout their range. Factors believed to play a part in this decline include pesticide spraying in Canadian and U.S. forests which have reduced spruce budworms, a favorite prey, and shrinking of boreal forests from climate warming and harvesting of old growth forests.
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