Once upon a time in Minnesota and east to the Atlantic coast, the spectacular evening grosbeak was a regular and often abundant winter visitor. The period of greatest abundance was roughly the 1940s to the mid-1980s. Rewind to the mid-19th century: At this time, evening grosbeaks had begun expanding their nesting range from western coniferous forests across to eastern Canada and the northeastern U.S. The reason for the expansion is not well understood. But it was real, and by the early 20th century, the species was well established in the East and had become a familiar winter bird in the northern and central states.
The evening grosbeak (not closely related to our rose-breasted grosbeak) is a large, stocky finch with a massive bill. The striking color combination of yellow, black, white and bronze is unique and, to me, one of the most beautiful combinations in the bird world I have seen.
In the nesting season, the male’s bill is almost chartreuse. The birds are rather shy and retiring when nesting, but in winter they are gregarious (often 50 or many more), noisy and voracious devourers of sunflower seeds at feeders. Appreciating them fully involves a willingness to spend a small fortune on bird seed or see them disappear as quickly as they arrived, only to raid someone else’s feeders.
Away from feeders they forage on a variety of natural seeds and fruits, especially those of maple, box elder and ash trees. But like all songbirds, their diet turns to high-protein sources like insects when they are feeding young. A favorite prey in the coniferous forests of the North is the spruce budworm. Some researchers believe the population fluctuations of the grosbeak are related to outbreaks of spruce budworm, irruptions of which occur in irregular cycles of 20 to 100 years. A major outbreak in eastern Canada in the mid-20th century coincided with the last population boom of the grosbeak. In past articles, I have mentioned that populations of certain other species like some warblers and the purple finch may rise and fall with spruce budworm cycles.
In the 1990s and into the 21st century when budworm populations were low, winter occurrences of the evening grosbeak in Minnesota and the East declined precipitously. In recent years outside of the Arrowhead, where they still breed in small numbers, they have been rare. I haven’t seen any in Park Rapids for about seven years.
But, because the spruce budworm is now beginning to reappear in eastern Canada, we may be on the cusp of a new incursion of evening grosbeaks. Dr. Alan Olander of Nevis sent me a photograph of two male evening grosbeaks at his place last week. A friend in Michigan reports that they are being seen in the southern lower peninsula after a long absence.
I suggest that, if you want to attract these amazing birds to your feeders, now may be the time for you to just bite the bullet, cut back on non-essential expenses and allocate a larger chunk of your budget to sunflower seed!
Marshall Howe is a retired biologist with the U.S. Fish and Wildlife Service. He specialized in bird population studies. Howe has been a Park Rapids resident since 2010.