Evening Grosbeak

Prior to the 1900s the Evening Grosbeak was rare in the east, but over time it gradually expanded from the Rocky Mountains and first bred in New England in the 1920s. By the 1940s and 1950s it was a reliable winter visitor, with larger numbers roughly every two years, and this pattern continued through the 1980s. Now, as anyone who remembers the invasion years (when grosbeaks descended on feeders by the dozens and cleaned them of sunflower seeds in a matter of hours) will tell you, the species has become extremely hard to find.

The Evening Grosbeak’s heyday in the Northeast, which lasted roughly from 1950 to 1990, coincided with a large outbreak of spruce budworm (a moth) in eastern Canada. As this outbreak started to wind down, the grosbeaks lost an abundant source of food and their populations declined or shifted west. Thus, while local breeding populations persisted for another decade, the huge winter numbers became a thing of the past in the absence of a large population to our north. But the budworm operates on a roughly 40-year cycle, and in the early 2000s a new one outbreak started in southern Quebec. Shortly thereafter the number of grosbeaks visiting New Hampshire started to grow again. You can see the early signs of this in the graph, and while we’re still a long way from the numbers during the last outbreak there are signs that there are more grosbeaks to come. Remember that peaks occur every other year, so there will still be winters where grosbeaks will be extremely hard to find.

Despite the signs of growing populations to the north, Evening Grosbeaks remain even rarer as a breeding bird in New Hampshire, with most records in the far north and a few in the southwest. And probably because it can be secretive when nesting, very little is known about its breeding biology. For a long time, it wasn’t even clear if the species had a song, and the one that exists is little more than a glorified version of the more familiar raucous calls heard at winter bird feeders. Even the name stems from the misconception that the bird only came out of the woods to sing at dusk.