Today’s story is about something that has already happened, and something else that might happen. Usually I focus in on one particular species, but this week I want to give you a rundown of the “Winter Finch Forecast” that is published annually by the Finch Research Network. This report is eagerly anticipated by many birders. Just last week, my brother and I had a fun conversation about its implications. So, to be clear, the forecast is not mine, but much of the explanation of the conditions leading up to the forecast is.
So, what has already happened? To put is simply, it was the spring and summer growing season for trees, and the annual breeding season for birds. Much more specifically, however, I am going to look at the growing season for spruce trees and the breeding season of the boreal finches; species like common redpolls, pine siskins, purple finches, evening grosbeaks, pine grosbeaks and two species of crossbills – the red and the white-winged.
We start with the spruce trees, because they are at the base of an interesting food web upon which everything else depends. Although they are scarce in Massachusetts, there are two species of native spruce trees that are common for us at the highest elevations. These are the red spruce (Picea rubens), the black spruce (P. mariana). A third species integral to the story, but absent from our area is the white spruce (P. glauca). These three species are part of the boreal forest that covers northern New England, most of Canada and interior Alaska.
As with any producers in a food web, there are herbivores that want to eat them. For the purposes of today’s story, we are going to focus on one particular insect – the eastern spruce budworm (Choristoneura fumiferana). This is actually a type of moth, but it gets its name from its larval stage (the caterpillar) which feeds extensively on spruce trees. These moths can do serious damage to spruce forests, and 2025 was a very good year for spruce budworms.
With so many caterpillars in the boreal forest, the birds that eat them had a fantastic breeding season and their respective populations have swelled in number with brood after brood of plump chicks fledging into the world. The fly in the ointment of our story is the fact that while the budworms (and the birds that eat them) had a very successful summer, the spruce trees themselves did not. Very few cones have been produced, and other species of trees (birch, alder and ash) have also struggled. This means that there are lots of birds, but not much in the way of winter food for them to eat.
This brings us to what might happen: a winter irruption of many boreal-forest birds to the south, which is right where we are. But first, a vocabulary review. Many people probably recognize of the word “eruption” as being associated with volcanoes. Basically, it describes a situation in which material is expelled from the Earth, but it can also refer to an emotional outburst. In contrast, the word “irruption” refers to a sudden increase in a population, or the range occupied by that population. At present, the conditions are set for a major irruptive event in which the northern finches must fan out in search of winter food.
This is different than the predictable annual migration of birds from north to south because the winter finches will basically stay put as long as there is enough food for them. In years when there aren’t many budworms, but there are plenty of spruce cones, the birds will just stay where they are. This year is not one of those years. The conditions were reversed and there are large numbers of birds that are going to go hunting for food. According to the Finch Research Network, there has been a “significant cone crop … from the Adirondack Mountains in New York, east through New England.” This puts us in a very good position to see many species of winter birds that only show up once in a while.
The smaller birds (siskins, redpolls and finches) don’t rely on the spruce trees for winter food because the seeds are too large for them do deal with. However, there are many varieties of seeds found in traditional birdseed mixes (millet and sunflower) that the little birds will happily gobble up. Best of all, if you are consistent in your offerings of food, you might convince a group of these nomadic birds to settle down in your yard for the duration of the winter.
The larger birds (grosbeaks and crossbills) are also happy to munch away on birdseed, but they may require a different presentation of the food. Smaller birds can easily perch on “tube” feeders, but the larger birds may enjoy a platform feeder more. This is a hanging feeder that is basically a tray on four chains; easy for a larger bird to perch on and eat from. Another great “platform” for food is a railing on your deck and the deck itself. Visit the FeederWatch Cam at the Cornell Lab of Ornithology for an example. Once any threat of bears has diminished for the season, put out food as consistently as possible and keep your eyes peeled. This could be a very good year for winter visitors.
Bill Danielson has been a professional writer and nature photographer for 28 years. He has worked for the National Park Service, the US Forest Service, the Nature Conservancy and the Massachusetts State Parks and he currently teaches high school biology and physics. For more information visit his website at www.speakingofnature.com, or go to Speaking of Nature on Facebook.