Some winters, Pine Siskins and Common Redpolls show up at nyjer feeders by the dozen. Other winters, they never appear at all — not because the weather wasn’t cold enough, but because the food wasn’t scarce enough. Understanding why takes a look at a tradition that has tracked this exact question since 1999: the Winter Finch Forecast.
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What the Winter Finch Forecast Actually Predicts
Each fall, the Finch Research Network publishes a species-by-species outlook based on one central variable: how heavy the seed crop is across the boreal forest of Canada that year. Spruce, pine, birch, and mountain-ash all produce seed and fruit in cycles that vary sharply from year to year, and finches track those crops far more closely than they track the calendar or the thermometer.
Why It’s Called an ‘Irruption,’ Not a Migration
As covered in our guide to finch migration patterns, most backyard birds follow a predictable seasonal migration. Pine Siskin and Common Redpoll do something different: they’re irruptive, meaning their movement south is driven entirely by food availability in a given year rather than a fixed annual route. In a bumper boreal seed-crop year, both species may stay north through the entire winter. In a poor-crop year, they push hundreds or even thousands of miles south in search of food, sometimes reaching states that rarely see them at all.
Reading a Forecast Year
| Boreal Seed Crop | Likely Result at Southern Feeders |
|---|---|
| Bumper crop (excellent) | Siskins and redpolls stay north; feeders in the U.S. see few or none |
| Average to good crop | Modest, patchy movement; some regions get flocks, others don’t |
| Poor crop (widespread) | Large-scale irruption; siskins and redpolls arrive in numbers, sometimes well south of their typical winter range |
This is why two consecutive winters can look completely different at the same feeder with no change in how it’s stocked. A host running the exact same setup covered in our nyjer seed guide might see zero siskins one year and a flock of forty the next — the difference is happening hundreds of miles north, in a spruce forest the feeder host will never see.
Pine Siskin vs. Common Redpoll: Different Triggers
While both species are irruptive, they don’t always move together. Pine Siskin tracks conifer seed crops — spruce, pine, and hemlock — and tends to irrupt in roughly alternating years, since a heavy cone crop is often followed by a lean one. Common Redpoll leans more heavily on birch and alder catkins, and its irruptions are documented to run on a longer, sometimes biennial cycle. In a genuinely poor year across multiple seed sources, the two species can irrupt together, producing the kind of dramatic flight years birders still talk about years later.
What About Purple Finch and Evening Grosbeak?
The forecast also tracks Purple Finch, Evening Grosbeak, Red and White-winged Crossbill, and Pine Grosbeak, though only Purple Finch is a regular backyard visitor across most of this network’s coverage area. Its movement follows the same basic logic — when hardwood seed and fruit crops run short in its northern breeding range, more individuals push south and linger longer at feeders stocked with sunflower, as described in our species identification guide.
How to Use the Forecast at Your Own Feeder
- Check the current season’s forecast at the Finch Research Network in early fall, before winter feeding season ramps up.
- If a poor boreal crop is forecast, keep nyjer feeders topped off and fresh — stale seed loses the oil content that draws siskins and redpolls in the first place.
- Don’t assume a quiet feeder means something is wrong with your setup; in a bumper-crop year, even a well-run feeding station may simply see fewer irruptive visitors.
- Report what you do see — citizen-science platforms like eBird feed directly into next year’s forecast.
The forecast isn’t a guarantee — it’s a probability based on real-time crop reports from foresters, biologists, and birders across the boreal region. But for anyone who wonders why their feeder is either overrun or eerily quiet in a given winter, it’s the single best explanation available, and it turns an unpredictable season into one you can actually plan around.
In an irruption year, a camera feeder like the Birdfy Feeder is a handy way to confirm what’s arrived, since it records and identifies each visitor automatically.
A Brief History Worth Knowing
The Winter Finch Forecast tradition dates back to 1999, when Ontario naturalist Ron Pittaway began posting an annual outlook to regional birding listservs based on his own crop surveys. What started as an informal, single-author forecast has grown into a network effort, drawing on cone and seed crop reports from foresters, biologists, and birders across a wide swath of the boreal forest each fall. After Pittaway’s death, the Finch Research Network took over stewardship of the forecast, continuing the same crop-based methodology that made the original version reliable enough to become an annual tradition for serious feeder watchers across North America.
Distinguishing a Forecast From a Guarantee
It’s worth being clear about what the forecast can and can’t predict. It describes regional trends based on crop surveys collected mainly across Ontario and adjacent provinces and states, and conditions can vary meaningfully within the broader area it covers. A forecast calling for a strong siskin flight doesn’t guarantee siskins at any specific feeder — local factors like nearby natural food, feeder density in the immediate neighborhood, and even short-term weather during migration all affect whether a regional trend translates into birds at a particular yard. Treating the forecast as a probability rather than a promise sets the right expectations going into the season.
Beyond Siskins and Redpolls
While Pine Siskin and Common Redpoll get most of the attention from backyard feeder hosts, the forecast also tracks species most readers of this guide won’t see at a nyjer feeder at all — Red and White-winged Crossbill, both conifer-cone specialists with bills adapted to pry seeds directly from unopened cones, and Pine Grosbeak and Evening Grosbeak, both larger finches that key more on fruit and bud crops than on the seed sources siskins and redpolls track. Watching the broader forecast, even for species that won’t show up at a typical backyard setup, gives a fuller picture of just how widely a single poor cone crop can ripple through an entire finch community across a continent.
