Michigan-based birdwatchers have their eyes set on the skies this fall, as unexpected visitors pass through the state in preparation for the developing winter. The phenomenon driving these visitations is known as an irruption, referring to the movements of northern-wintering species to the south during years of low food availability. This year, all across east North America, countless flocks have wandered outside their normal ranges into the upper Great Lakes, Midwest, and Northeast regions. Among them are various species of Finches, Waxwings, Grosbeaks, Chickadees, Redpolls, and other birds all in search of new food sources for the winter.
Some of the specific species that have been sighted so far include the evening grosbeaks – stout yellow finches with striking lines of black and white. They’ve been seen snacking on sunflower seeds at bird feeders across the Lower Peninsula, outside their typical foraging areas. Red-breasted Nuthatches have also been spotted snatching up peanuts, suet and other high-fat snacks. Flocks of common Redpolls, along with their subspecies, the Hoary Redpolls, have been seen on birches, in weedy fields, and passing through to feeders that offer thistle and black-oil sunflower seeds. While some species like the Bohemian Waxwing have unpredictable movement patterns, reports of sightings have increased, with the bird even seen mixing into flocks of Robins and Cedar Waxwings, in search of abundant findings of buckthorn berries, mountain-ash berries, and even ornamental crabapples.
Irruptions are sporadic events, never following any discernible patterns from year to year due to their being based on the availability – or lack thereof – of particular food sources like pine cones, birch seeds, and mountain-ash berries. These can also widely vary in scale, frequency, and even in the behavior of the different species. On one occasion, a flock may choose to stay in one location for weeks at a time, however, on another occasion they may choose instead to only remain in the area for a single day. It’s this unpredictability that adds to the excitement of birdwatchers from every corner of the state and beyond. The last irruption to take place in Michigan was in late 2020, when experts declared it the biggest in two decades.
Each year, the likelihood and scale of possible irruptions is published online in the Winter Finch Forecast by the Finch Research Network. Predictions are made based on the recorded levels of food sources for Canadian wild birds. According to the forecast for 2022, many more species will surely be venturing south into the Great Lakes region this winter, so get your feeders ready and rolled out to offer a warm welcome to these little travelers.